WowAce

The addon doesn't work on the latest version of WoW, giving this Lua Warning:

Message: Interface\AddOns\Castbars\Castbars.lua:1: Cannot find a library instance of "AceAddon-3.0".
Time: Thu Dec 10 23:22:16 2020
Count: 1
Stack: Interface\AddOns\Castbars\Castbars.lua:1: Cannot find a library instance of "AceAddon-3.0".
[string "=[C]"]: in function `error'
[string "@Interface\AddOns\BagBrother\LibStub.lua"]:23: in function `LibStub'
[string "@Interface\AddOns\Castbars\Castbars.lua"]:1: in main chunk

Locals: (*temporary) = "Cannot find a library instance of "AceAddon-3.0"."

Message: (null)
Time: Thu Dec 10 23:22:17 2020
Count: 3

It doesn't work here either. I was about to open up a ticket...

Repeating the same, will not load using either /cb or /castbars. Game addon list shows "checkmark" as enabled, but does not appear on the interface list. Recently installed today - 12/23/20.

You've probably used the Curseforge program to install it, for some insane reason it installs the 9.0-nolib version, which doesn't have the libraries. Go and manually select to install the 9.0 version, from the Files tab on the website here, that will work.

Yeah, the one from here somehow works, but everytime you try to cast something it returns an error:

Message: Interface\AddOns\Castbars\Castbars.lua:211: attempt to call method 'show' (a nil value)
Time: Tue Jan 5 22:45:17 2021
Count: 1
Stack: Interface\AddOns\Castbars\Castbars.lua:211: attempt to call method 'show' (a nil value)
[string "@Interface\AddOns\Castbars\Castbars.lua"]:211: in function `FrameIconRestore'
[string "@Interface\AddOns\Castbars\Castbars.lua"]:279: in function `FrameDynamicRestore'
[string "@Interface\AddOns\Castbars\Castbars.lua"]:1499: in function <Interface\AddOns\Castbars\Castbars.lua:1414>

Locals: self = <table> {
SetDefaultModuleLibraries = <function> defined @Interface\AddOns\Castbars\Libs\AceAddon-3.0\AceAddon-3.0.lua:367
DoNothing = <function> defined @Interface\AddOns\Castbars\Castbars.lua:4
FrameIconRestore = <function> defined @Interface\AddOns\Castbars\Castbars.lua:185
FrameTimerRestore = <function> defined @Interface\AddOns\Castbars\Castbars.lua:134
CastingBarFrame_OnUpdate = <function> defined @Interface\AddOns\Castbars\Castbars.lua:1383
FrameMediaRestoreAll = <function> defined @Interface\AddOns\Castbars\Castbars.lua:128
modules = <table> {
}
baseName = "Castbars"
IterateEmbeds = <function> defined @Interface\AddOns\Castbars\Libs\AceAddon-3.0\AceAddon-3.0.lua:442
OnDragStart = <function> defined @Interface\AddOns\Castbars\Castbars.lua:425
FrameMediaRestore = <function> defined @Interface\AddOns\Castbars\Castbars.lua:98
Printf = <function> defined @Interface\AddOns\Castbars\Libs\AceConsole-3.0\AceConsole-3.0.lua:69
SetDefaultModulePrototype = <function> defined @Interface\AddOns\Castbars\Libs\AceAddon-3.0\AceAddon-3.0.lua:409
Show = <function> defined @Interface\AddOns\Castbars\Castbars.lua:1572
defaultModuleState = true
IsEnabled = <function> defined @Interface\AddOns\Castbars\Libs\AceAddon-3.0\AceAddon-3.0.lua:451
DisableModule = <function> defined @Interface\AddOns\Castbars\Libs\AceAddon-3.0\AceAddon-3.0.lua:350
CastingBarFrameTicksSet = <function> defined @Interface\AddOns\Castbars\Castbars.lua:43
FrameLatencyQueueRestore = <function> defined @Interface\AddOns\Castbars\Castbars.lua:218
FrameTextRestore = <function> defined @Interface\AddOns\Castbars\Castbars.lua:252
frames = <table> {
}
MirrorTimer_Show = <function> defined @Interface\FrameXML\MirrorTimer.lua:18
Toggle = <function> defined @Interface\AddOns\Castbars\Castbars.lua:1626
MirrorTimerFrame_OnUpdate = <function> defined @Interface\AddOns\Castbars\Castbars.lua:1402
SetEnabledState = <function> defined @Interface\AddOns\Castbars\Libs\AceAddon-3.0\AceAddon-3.0.lua:424
enabledState = true
IsDualWielding = <function> defined @Interface\AddOns\Castbars\Castbars.lua:76
IterateModules = <function> defined @Interface\AddOns\Castbars\Libs\AceAddon-3.0\AceAddon-3.0.lua:437
OnKeyUp = <function> defined @Interface\AddOns\Castbars\Castbars.lua:443
FrameDynamicRestore = <function> defined @Interface\AddOns\Castbars\Castbars.lua:277
RegisterChatCommand = <function> defined @Interface\AddOns\Castbars\Libs\AceConsole-3.0\AceConsole-3.0.lua:85
GetModule = <function> defined @Interface\AddOns\Castbars\Libs\AceAddon-3.0\AceAddon-3.0.lua:210
defaultModuleLibraries = <table> {
}
Hide = <function> defined @Interface\AddOns\Castbars\Castbars.lua:1608
UnregisterChatCommand = <function> defined @Interface\AddOns\Castbars\Libs\AceConsole-3.0\AceConsole-3.0.lua:111
options = <table> {
}
GetName = <function> defined @Interface\AddOns\Castbars\Libs\AceAddon-3.0\AceAddon-3.0.lua:279
FrameLayoutRestoreAll = <function> defined @Interface\AddOns\Castbars\Castbars.lua:363
SharedMedia = <table> {
}
UnitFullName = <function> defined @Interface\AddOns\Castbars\Castbars.lua:1208
Barticks = <table> {
}
playerClass = "DRUID"
orderedModules = <table> {
}
Disable = <function> defined @Interface\AddOns\Castbars\Libs\AceAddon-3.0\AceAddon-3.0.lua:314
CastingBarFrame_OnEvent = <function> defined @Interface\AddOns\Castbars\Castbars.lua:1414
Print = <function> defined @Interface\AddOns\Castbars\Libs\AceConsole-3.0\AceCo