I'm Using version 3.0.10.3

I keep getting a dialog box popping up at arbirtary moments with the error below listed. I haven't noticed anything particular about when/why in order to recreate it though. Sorry to be so vague.

Date: 2009-04-04 08:15:53
ID: 1
Error occured in: Global
Count: 1
Message: ...dyNotes_SpecialNPCsEtc\HandyNotes_SpecialNPCsEtc.lua line 407:
   bad argument #1 to 'strlen' (string expected, got nil)
Debug:
   (tail call): ?
   (tail call): ?
   [C]: strlen()
   ...dyNotes_SpecialNPCsEtc\HandyNotes_SpecialNPCsEtc.lua:407 Opened_NPC()
   ...dyNotes_SpecialNPCsEtc\HandyNotes_SpecialNPCsEtc.lua:392 ?()
   ...er3\libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:146
      ...er3\libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:146
   [string "safecall Dispatcher[1]"]:4:
      [string "safecall Dispatcher[1]"]:4
   [C]: ?
   [string "safecall Dispatcher[1]"]:13: ?()
   ...er3\libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:91 Fire()
   ...AddOns\HandyNotes\Libs\AceEvent-3.0\AceEvent-3.0.lua:70
      ...AddOns\HandyNotes\Libs\AceEvent-3.0\AceEvent-3.0.lua:69
AddOns:
  Swatter, v3.1.11 (<%codename%>)
  AdvancedTradeSkillWindow, v
  AutoRepair, v
  Babylonian, v5.1.DEV.130
  BlizzMove, v0.2
  Cartographer3, v3.0 v0.10.3
  Cartographer3InstancePOIs, v
  Cartographer3Notes, v
  Cartographer3Waypoints, v
  Configator, v5.1.DEV.160
  CurseProfiler, v
  Gatherer, v3.1.11
  HandyNotes, v1.1.3
  HandyNotesCityGuide, v1.0.0
  HandyNotesDirections, v1
  HandyNotesFlightMasters, v1.0.2
  HandyNotesGuild, v1.0
  HandyNotesHigherLearning, v1.0.0
  HandyNotesLunarElders, v1.0.0
  HandyNotesMailboxes, v1
  HandyNotesOpenPVP, v1
  HandyNotesQuestGivers, v0.1.0
  HandyNotesSpecialNPCsEtc, v0.0.1
  HandyNotesTrainers, v1.1.7
  HandyNotesVendors, v1.1.3
  ItemPriceTooltip, v88
  iTracking, v
  LearningAid, v
  MailSound, v
  QuestHelper, v0.95
  QuestItem, v1.22
  SlideBar, v3.1.11 (<%codename%>)
  TNoDuel, v1.1.0
  WhereToNow, v1.6
  (ck=360)