I find the below will fix my issues when I have issues:

Open up the pitbull config > Click units > Disable and then renable the first frame

This fixes the issue every time for me.

Swatter error on login (also - blank unit frames)  Hope this helps in some way ...

Date: 2013-09-21 22:57:48

ID: 1

Error occured in: Global
Count: 1
Message: PitBull4_LuaTexts:Normal:Lua:Name caused the following error when calling SetFont(nil,3.3850262548614e-035,nil):
Usage: PitBull4_FontString_3:SetFont("font", fontHeight [, flags])
Debug:
[C]: pcall()
PitBull4_LuaTexts\LuaTexts.lua:843:
PitBull4_LuaTexts\LuaTexts.lua:838
PitBull4_LuaTexts\LuaTexts.lua:902:
PitBull4_LuaTexts\LuaTexts.lua:856
PitBull4_LuaTexts\LuaTexts.lua:1445: AddFontString()
...ddOns\PitBull4\ModuleHandling\TextProviderModule.lua:118: UpdateFrame()
PitBull4\ModuleHandling\Module.lua:319: Update()
PitBull4\UnitFrame.lua:810: Update()
PitBull4\UnitFrame.lua:728: RecheckConfigMode()
PitBull4\Options\ConfigMode.lua:58: RecheckConfigMode()
PitBull4\Main.lua:1347: OnProfileChanged()
PitBull4\Main.lua:1412:
PitBull4\Main.lua:1382
(tail call): ?
[C]: ?
[string "safecall Dispatcher[1]"]:9:
[string "safecall Dispatcher[1]"]:5
(tail call): ?
...s\AckisRecipeList\libs\AceAddon-3.0\AceAddon-3.0.lua:558: EnableAddon()
...s\AckisRecipeList\libs\AceAddon-3.0\AceAddon-3.0.lua:651:
...s\AckisRecipeList\libs\AceAddon-3.0\AceAddon-3.0.lua:636
[C]: LoadAddOn()
..\FrameXML\UIParent.lua:303: UIParentLoadAddOn()
..\FrameXML\UIParent.lua:326: CombatLog_LoadUI()
..\FrameXML\UIParent.lua:739:
..\FrameXML\UIParent.lua:702
Locals:
None
AddOns:
Swatter, v5.18.5433 (PassionatePhascogale)
NPCScan, v5.0.0.5
NPCScanOverlay, v5.0.0.3
AckisRecipeList, v2.5.2-9-g253ee50
ACP, v3.4.4
afkquit, v2.4 (r16)
AllPlayed, v50300-1 $Revision: 287 $
AltTabber, v1.9.3
ArkAutoLootBoP, v11200
ArkInventory, v30331
ArkInventoryRules, v
AskMrRobot, v1.1.10.0
AtlasLoot, vv7.07.01
AtlasLootCataclysm, vv7.07.01
AtlasLootClassicWoW, vv7.07.01
AtlasLootLoader, vv7.07.01
AtlasLootMistsofPandaria, vv7.07.01
AucAdvanced, v5.18.5433 (PassionatePhascogale)
AucFilterBasic, v5.18.5433 (PassionatePhascogale)
AucFilterOutlier, v5.18.5433.5347(5.18/embedded)
AucMatchUndercut, v5.18.5433.5364(5.18/embedded)
AucStatHistogram, v5.18.5433 (PassionatePhascogale)
AucStatiLevel, v5.18.5433 (PassionatePhascogale)
AucStatPurchased, v5.18.5433 (PassionatePhascogale)
AucStatSales, v5.18.5433.5376(5.18/embedded)
AucStatSimple, v5.18.5433 (PassionatePhascogale)
AucStatStdDev, v5.18.5433 (PassionatePhascogale)
AucStatWOWEcon, v5.18.5433.5323(5.18/embedded)
AucUtilAHWindowControl, v5.18.5433.5347(5.18/embedded)
AucUtilAppraiser, v5.18.5433.5427(5.18/embedded)
AucUtilAskPrice, v5.18.5433.5347(5.18/embedded)
AucUtilAutoMagic, v5.18.5433.5415(5.18/embedded)
AucUtilCompactUI, v5.18.5433.5427(5.18/embedded)
AucUtilEasyBuyout, v5.18.5433.5427(5.18/embedded)
AucUtilFixAH, v5.18.5433 (PassionatePhascogale)
AucUtilItemSuggest, v5.18.5433.5417(5.18/embedded)
AucUtilPriceLevel, v5.18.5433.5427(5.18/embedded)
AucUtilScanButton, v5.18.5433.5403(5.18/embedded)
AucUtilScanFinish, v5.18.5433.5347(5.18/embedded)
AucUtilScanProgress, v5.18.5433.4979(5.18/embedded)
AucUtilScanStart, v5.18.5433.5347(5.18/embedded)
AucUtilSearchUI, v5.18.5433.5373(5.18/embedded)
AucUtilSimpleAuction, v5.18.5433.5415(5.18/embedded)
AucUtilVendMarkup, v5.18.5433.4828(5.18/embedded)
AutoInstantSummon, v
Babylonian, v5.1.DEV.332(/embedded)
BadBoy, v12.042
BadBoyCCleaner, v3.66
BadBoyGuilded, v2.93
BankStack, vv33
Bazooka, vv2.2.5
BeanCounter, v5.18.5433 (PassionatePhascogale)
BittensSpellFlashLibrary, v50400.1.5
BittensUtils, v50400.1.1
BrokerEverything, v5.2.1
BrokerEverythingConfig, v0.5
CloakHelmToggle, v1.0.0.5
CollectMe, v2.4.5
Configator, v5.1.DEV.344(/embedded)
Critline, vr82
CritlineAuraMonitor, vr82
DBMCore, v
DBMSpellTimers, v
DebugLib, v5.1.DEV.337(/embedded)
Decursive, v2.7.3
Dominos, v5.4.2
DominosEncounter, v
DominosPetBattles, v3
DominosRoll, v
DominosXP, v
EasyTradeSkills, vv5.4.0.0
Enchantrix, v5.18.5433 (PassionatePhascogale)
EnchantrixBarker, v5.18.5433 (PassionatePhascogale)
Fizzle, v50400-1
GTFO, v4.24.1a
HandyNotes, v1.2.0
HandyNotesTimelessIsleRareElites, v1.3
HandyNotesTimelessIsleChests, v1.09
InlineAura, vv1.8.12
InlineAuraDefaults, vv1.8.12
LibExtraTip, v5.12.DEV.355(/embedded)
LibSharedMedia30, v3.0-81
LightHeaded, v365
LunarSphere, v1.09
MikScrollingBattleText, v5.7.131
MillHelp, vr144
MillHelpGlyphs, vr144
norolecheckspam, vv1.2.2
NPCScanEx, v1.2.3
outofdateminder, v4.3.0
Outfitter, v5.9.2
PeonQuestComplete, v2013.09.10
PitBull4, vv4.0.0-beta47-7-g82a3dda
PitBull4Aggro, vv4.0.0-beta47-7-g82a3dda
PitBull4Aura, vv4.0.0-beta47-7-g82a3dda
PitBull4Background, vv4.0.0-beta47-7-g82a3dda
PitBull4BattlePet, vv4.0.0-beta47-7-g82a3dda
PitBull4BlankSpace, vv4.0.0-beta47-7-g82a3dda
PitBull4Border, vv4.0.0-beta47-7-g82a3dda
PitBull4CastBar, vv4.0.0-beta47-7-g82a3dda
PitBull4CastBarLatency, vv4.0.0-beta47-7-g82a3dda
PitBull4CombatFader, vv4.0.0-beta47-7-g82a3dda
PitBull4CombatIcon, vv4.0.0-beta47-7-g82a3dda
PitBull4CombatText, vv4.0.0-beta47-7-g82a3dda
PitBull4ComboPoints, vv4.0.0-beta47-7-g82a3dda
PitBull4ExperienceBar, vv4.0.0-beta47-7-g82a3dda
PitBull4HealthBar, vv4.0.0-beta47-7-g82a3dda
PitBull4HideBlizzard, vv4.0.0-beta47-7-g82a3dda
PitBull4Highlight, vv4.0.0-beta47-7-g82a3dda
PitBull4HostilityFader, vv4.0.0-beta47-7-g82a3dda
PitBull4LeaderIcon, vv4.0.0-beta47-7-g82a3dda
PitBull4LuaTexts, vv4.0.0-beta47-7-g82a3dda
PitBull4MasterLooterIcon, vv4.0.0-beta47-7-g82a3dda
PitBull4PhaseIcon, vv4.0.0-beta47-7-g82a3dda
PitBull4Portrait, vv4.0.0-beta47-7-g82a3dda
PitBull4PowerBar, vv4.0.0-beta47-7-g82a3dda
PitBull4PvPIcon, vv4.0.0-beta47-7-g82a3dda
PitBull4QuestIcon, vv4.0.0-beta47-7-g82a3dda
PitBull4RaidTargetIcon, vv4.0.0-beta47-7-g82a3dda
PitBull4RangeFader, vv4.0.0-beta47-7-g82a3dda
PitBull4ReadyCheckIcon, vv4.0.0-beta47-7-g82a3dda
PitBull4ReputationBar, vv4.0.0-beta47-7-g82a3dda
PitBull4RestIcon, vv4.0.0-beta47-7-g82a3dda
PitBull4RoleIcon, vv4.0.0-beta47-7-g82a3dda
PitBull4Shields, v1.3.9
PitBull4Sounds, vv4.0.0-beta47-7-g82a3dda
PitBull4ThreatBar, vv4.0.0-beta47-7-g82a3dda
PitBull4Totems, vv4.0.0-beta47-7-g82a3dda
PitBull4VisualHeal, vv4.0.0-beta47-7-g82a3dda
PitBull4VoiceIcon, vv4.0.0-beta47-7-g82a3dda
Postal, v3.5.1
Prat30, vr912
Prat30HighCPUUsageModules, v
Prat30Libraries, v
ProfessionsVault, vr507
Quartz, v3.1.3-4-g03c5ce4
RaidBuffStatus, v5.7.1
RareCoordinator, v
RSA, v2.855
RSAMage, v
SavedInstances, vr346
serverrestartsound, vv5
SexyMap, v2.4.9
SharedMedia, v3.0.5-184
SharedMediaClassicalFonts, vRelease 1.0.4
SharedMediaRenaitre, v5.4
SharedMediaAdditionalFonts, v1.0.16
SharedMediaAdditionalSounds, v1.1
Skinner, vb5.17539.1
slashtreasure, v1.0.1
SmartBuff, v5.4a
SpellFlash, v6.8.1
SpellFlashCore, v2.0.4
Stubby, v5.18.5433 (PassionatePhascogale)
SunnArt, v3.68
SunnArtPack1, v1.14
SunnArtPack2, v1.14
SunnArtPack3, v1.14
SunnArtPack4, v1.14
SunnArtPack5, v1.14
tekticles, v5.1.0.16
TidyPlates, v6.12.5
TidyPlatesGraphite, v
TidyPlatesGrey, v
TidyPlatesNeon, v
TidyPlatesQuatre, v
TidyPlatesHub, v
TidyPlatesWidgets, v
TipHelper, v5.12.DEV.351(/embedded)
TipTac, v13.09.21
TipTacItemRef, v13.09.21
TipTacTalents, v13.09.21
TomTom, vv50400-1.0.0
UndressButton, v5.3
Unmuter, v0.12
VEMCore, v
Volumizer, v5.3.0-2.2
VuhDo, v3.53
VuhDoOptions, v3.53
WeakAuras, vr306
BlizRuntimeLib_enUS v5.4.0.50400 <us>
(ck=1809)

For everyone experiencing the "blank unit frames" bug: when you log in, go to pitbull options > Layout Editor > Texts tab, and click on the "Default Font" dropdown field.  If your system is like mine, you will notice a very brief pause.  The fonts are now loaded, and your unit frames should behave normally upon a reload.  You do not need to select another default font, just bring up the drop menu.  Hope this helps. xoxo -Mooseykins.

I also experience problems, with the blank frames, when i log in. I've tried to reinstall the addon, but with no luck :-(

- It could be awesome with an update :-)

Everyone wearing pirate hats was for the in-game "Pirate's Day" holiday yesterday. ;) Everything should be back to normal today (and not a moment too soon, Pandaren with Pirate hats look awful, ugh!).

Also, I went over to the wowace site as Eincrou below mentioned and downloaded the Alpha v4.0.0-beta47-3-g8053a6d from Sep 14, 2013. I logged in on a character that couldn't heal themselves (since that was how I was "fixing" my frames before) and viola! Perfect frames on the first try with no .lua errors!

http://www.wowace.com/addons/pitbull4/files/

I think I love you both, Eincrou for pointing out the correct Alpha and Shefki for making it! *big squishy Panda hugs*

Since the patch I have 3 issues with pitbull:

- All players are wearing pirate hats... although its fine now
- After logging into the game I have to /reload UI or change anything in the player panel, otherwise its blank (mentioned several times)

- Now the 3rd issue is the worst. Frames are colored by aggro(?), instead of color by class... Tried to fix it by checking/unchecking options in the Bars->Health bar panel in each layout, but issue persists. Anyone else has noticed it? 

For some reason my frames show my characters as pirates.

I got player frame blank and this errror recurring

12x PitBull4_LuaTexts:Player:Lua:Class caused the following error when calling SetFont(nil,0,nil):
Usage: PitBull4_FontString_6:SetFont("font", fontHeight [, flags])
PitBull4_LuaTexts-v4.0.0-beta47-7-g82a3dda\LuaTexts.lua:843: in function <PitBull4_LuaTexts\LuaTexts.lua:838>
PitBull4_LuaTexts-v4.0.0-beta47-7-g82a3dda\LuaTexts.lua:902: in function <PitBull4_LuaTexts\LuaTexts.lua:856>
PitBull4_LuaTexts-v4.0.0-beta47-7-g82a3dda\LuaTexts.lua:1445: in function "AddFontString"
PitBull4-v4.0.0-beta47-7-g82a3dda\ModuleHandling\TextProviderModule.lua:118: in function "UpdateFrame"
PitBull4-v4.0.0-beta47-7-g82a3dda\ModuleHandling\Module.lua:319: in function "Update"
PitBull4-v4.0.0-beta47-7-g82a3dda\UnitFrame.lua:810: in function "Update"
PitBull4-v4.0.0-beta47-7-g82a3dda\UnitFrame.lua:728: in function "RecheckConfigMode"
PitBull4-v4.0.0-beta47-7-g82a3dda\Options\ConfigMode.lua:58: in function "RecheckConfigMode"
PitBull4-v4.0.0-beta47-7-g82a3dda\Main.lua:1347: in function "OnProfileChanged"
PitBull4-v4.0.0-beta47-7-g82a3dda\Main.lua:1412: in function <PitBull4\Main.lua:1382>
(tail call): ?
<in C code>
<string>:"safecall Dispatcher[1]":9: in function <string>:"safecall Dispatcher[1]":5
(tail call): ?
AutoProfitX-r84\Libs\AceAddon-3.0\AceAddon-3.0-12.lua:558: in function "EnableAddon"
AutoProfitX-r84\Libs\AceAddon-3.0\AceAddon-3.0-12.lua:651: in function <AutoProfitX\Libs\AceAddon-3.0\AceAddon-3.0.lua:636>
<in C code>
FrameXML\UIParent.lua:303: in function "UIParentLoadAddOn"
FrameXML\UIParent.lua:326: in function "CombatLog_LoadUI"
FrameXML\UIParent.lua:739: in function <FrameXML\UIParent.lua:702>

Locals:
nil

I have the same problem with Player frame being blank on login. 

I have to enter settings, change font to something else and it shows.

For reference, I use a named profile for the player frame (justme).

I also tried the latest beta as at the time of this post and the one below (..g8053a6d) but neither fixed it. In fact both made it worse as it also effected other frames.

 Even worse for me now, reverting to last beta build and I have lost fonts on all other frames like my target :(

Please fix as this has been my preferred frame addon for years and really dont want to switch to another

I have that too but only on one toon. If you have seperate settings for each char, you might have a char that uses a similar design. Just go to profiles and copy the working profile to the toon with the "broken" profile.

I was having the SetFont error a few days ago, but v4.0.0-beta47-3-g8053a6d fixed it  for me.

The latest set of Alphas give me many errors and I have reinstalled the alpha from two days ago.  Pitbull works fine. Thanks for your work on this project and I hope you can find a solution to these people's issues.

I actually get LUA errors although all my frames (player, target & target´s target) are doing fine. I figured out that all errors (14 overall) only appear on my mainchar, a druid, when i shapeshift into the several forms. This extends to the selfheals from Leader of the Pack or Frenzied Regeneration.

First LUA error:

Message: Interface\FrameXML\UnitFrame.lua:232: attempt to index field 'otherHealPrediction' (a nil value)
Time: 09/15/13 13:22:29
Count: 1
Stack: Interface\FrameXML\UnitFrame.lua:232: in function `UnitFrameHealPredictionBars_Update'
Interface\FrameXML\UnitFrame.lua:563: in function `UnitFrameHealthBar_Update'
Interface\FrameXML\UnitFrame.lua:158: in function <Interface\FrameXML\UnitFrame.lua:148>
[C]: in function `securecall'
Interface\FrameXML\UnitFrame.lua:145: in function `UnitFrame_SetUnit'
Interface\FrameXML\PlayerFrame.lua:380: in function `PlayerFrame_ToPlayerArt'
Interface\FrameXML\PlayerFrame.lua:145: in function `OnEvent'
Interface\FrameXML\UnitFrame.lua:679: in function <Interface\FrameXML\UnitFrame.lua:677>

Locals: frame = PlayerFrame {
 0 = <userdata>
 portrait = PlayerPortrait {
 }
 healAbsorbBar = PlayerFrameHealAbsorbBar {
 }
 statusSign = -1
 unit = "player"
 healAbsorbBarRightShadow = PlayerFrameHealAbsorbBarRightShadow {
 }
 healAbsorbBarLeftShadow = PlayerFrameHealAbsorbBarLeftShadow {
 }
 feedbackText = PlayerHitIndicator {
 }
 totalAbsorbBar = PlayerFrameTotalAbsorbBar {
 }
 totalAbsorbBarOverlay = PlayerFrameTotalAbsorbBarOverlay {
 }
 statusCounter = 0
 healthbar = PlayerFrameHealthBar {
 }
 overAbsorbGlow = PlayerFrameOverAbsorbGlow {
 }
 manabar = PlayerFrameManaBar {
 }
 inSequence = false
 threatIndicator = PlayerFrameFlash {
 }
 state = "player"
 myHealPredictionBar = PlayerFrameMyHealPredictionBar {
 }
 name = PlayerName {
 }
 menu = <function> defined @Interface\FrameXML\PlayerFrame.lua:51
 feedbackFontHeight = 30
 OnEvent = <function> defined @Interface\FrameXML\PlayerFrame.lua:127
 otherHealPredictionBar = PlayerFrameOtherHealPredictionBar {
 }
 overHealAbsorbGlow = PlayerFrameOverHealAbsorbGlow {
 }
}
_ = 0
maxHealth = 586910
health = 586910
(*temporary) = nil
(*temporary) = nil
(*temporary) = <userdata>
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = "attempt to index field 'otherHealPrediction' (a nil value)"
MAX_INCOMING_HEAL_OVERFLOW = 1

Still experiencing issues with target frame producing LUA errors.  Upon logging in, I am presented with a similar LUA error to those below.  The fix is to change the target frame's default text size to anything but what it is currently set to.  I normall have the default size at 100 percent, and changing it to 99, or 99.5, or anything else makes to LUA go away and the frame appear.  So my login experience upon a fresh playing of WoW consists of:

Login, target something, LUA error, open Pitbull, change target frame's default text size to anything I want, problem disappears.

I can change toons and the problem does not persist, however, if I completely leave the game and then restart WoW, the problem reappears.

I'm having the exact same issue as Napayshni. Upon login my player frame is solid green. /reload does not fix the issue, relogging does not fix the issue. Casting a heal spell does seem to fix it half way, where everything is in the right place but there is no text. AFTER casting a heal spell I need to /reload to get the text to appear. After all of that I can go without any firther issues.

I've been experiencing similar problems to a lot of posters, where my frames aren't showing up properly. My player frame is a solid-colored block with no portrait, no text, no cast bar, nothing. My target doesn't appear at all. (If I hover over where my target frame should be, it highlights the invisible frame but all I see is the highlight overlay.)

If I heal myself it'll "refresh" the frame or something and everything will reappear as it's supposed to after a few casts. (The first time my portrait and mana bar appear, and the target/targetoftarget frames appear again. It takes a few more casts to get text to show up on my player frame.) If I'm not on a healer though, I don't know how to fix the bars and make them appear and/or display properly.

Unlike everyone else, the "fixes" don't work for me. I tried changing the font sizes (100% to 95%) and all that does is make another lua error appear on my screen. I tried the "just /reload after you first log in" that a few people have said worked for them, and nothing: still a blank character bar and no target bar.

When I log in, I get 27 LUA errors so I'm not sure which one to post... I can post all of them if you want. They all say PitBull4 or FrameXML in them. Here are the first two. If I target someone/something, I get another three errors, one of which is counting constantly with tons of errors every second. (50-70+ ish per second, and if I deselect my target it stops counting immediately.)

Message: Interface\AddOns\PitBull4_LuaTexts\LuaTexts.lua:886: Usage: PitBull4_FontString_1:SetFont("font", fontHeight [, flags])
Time: 09/14/13 17:10:44
Count: 1
Stack: (tail call): ?
[C]: in function `SetFont'
Interface\AddOns\PitBull4_LuaTexts\LuaTexts.lua:886: in function <Interface\AddOns\PitBull4_LuaTexts\LuaTexts.lua:839>
Interface\AddOns\PitBull4_LuaTexts\LuaTexts.lua:1429: in function `AddFontString'
...ddOns\PitBull4\ModuleHandling\TextProviderModule.lua:118: in function `UpdateFrame'
Interface\AddOns\PitBull4\ModuleHandling\Module.lua:319: in function `Update'
Interface\AddOns\PitBull4\UnitFrame.lua:808: in function `Update'
Interface\AddOns\PitBull4\UnitFrame.lua:728: in function `RecheckConfigMode'
Interface\AddOns\PitBull4\Options\ConfigMode.lua:58: in function `RecheckConfigMode'
Interface\AddOns\PitBull4\Main.lua:1347: in function `OnProfileChanged'
Interface\AddOns\PitBull4\Main.lua:1412: in function <Interface\AddOns\PitBull4\Main.lua:1382>
(tail call): ?
[C]: ?
[string "safecall Dispatcher[1]"]:9: in function <[string "safecall Dispatcher[1]"]:5>
(tail call): ?
...s\AckisRecipeList\libs\AceAddon-3.0\AceAddon-3.0.lua:558: in function `EnableAddon'
...s\AckisRecipeList\libs\AceAddon-3.0\AceAddon-3.0.lua:651: in function <...s\AckisRecipeList\libs\AceAddon-3.0\AceAddon-3.0.lua:636>
[C]: in function `LoadAddOn'
Interface\FrameXML\UIParent.lua:303: in function `UIParentLoadAddOn'
Interface\FrameXML\UIParent.lua:326: in function `CombatLog_LoadUI'
Interface\FrameXML\UIParent.lua:739: in function <Interface\FrameXML\UIParent.lua:702>

Locals: <none>

Message: Interface\FrameXML\UnitFrame.lua:232: attempt to index field 'otherHealPrediction' (a nil value)
Time: 09/14/13 17:10:44
Count: 1
Stack: [C]: ?
Interface\FrameXML\UnitFrame.lua:232: in function `UnitFrameHealPredictionBars_Update'
Interface\FrameXML\UnitFrame.lua:563: in function `UnitFrameHealthBar_Update'
Interface\FrameXML\UnitFrame.lua:158: in function <Interface\FrameXML\UnitFrame.lua:148>
[C]: in function `securecall'
Interface\FrameXML\UnitFrame.lua:145: in function `UnitFrame_SetUnit'
Interface\FrameXML\PlayerFrame.lua:380: in function `PlayerFrame_ToPlayerArt'
Interface\FrameXML\PlayerFrame.lua:145: in function `OnEvent'
Interface\FrameXML\UnitFrame.lua:679: in function <Interface\FrameXML\UnitFrame.lua:677>

Locals:

Is there a reason why i cannot inspect players when i right click on the unit frame? is a limitation of the addon or am i doing something wrong? thanks