When the problem happens
1. Someone joins the party (occasionally)
2. Random points during the day (rarely)
3. When I hit level 70... (>_> Very odd this one was)

What is the expected output? What do you see instead?
I don't know, it just pops up this error

What version of the product are you using?
The most recent, available to the Curse Client

Do you have an error log of what happened?
Date: 2009-05-08 00:03:53
ID: 1
Error occured in: Global
Count: 1
Message: ..\AddOns\DoTimer\Notifications\events.lua line 114:
   Usage: UnitIsUnit("unit", "otherUnit")
Debug:
   (tail call): ?
   [C]: ?
   [C]: UnitIsUnit()
   DoTimer\Notifications\events.lua:114 ?()
   DoTimer\Notifications\events.lua:51
      DoTimer\Notifications\events.lua:50
AddOns:
  Swatter, v5.4.4157 (WallabyII)
  Ace2, v
  Ace3, v
  AucAdvanced, v5.4.4157 (WallabyII)
  AucFilterBasic, v5.4.4157 (WallabyII)
  AucFilterOutlier, v5.4.4157.2531
  AucMatchUndercut, v5.4.4157.2531
  AucScanData, v5.4.4157 (WallabyII)
  AucStatClassic, v5.4.4157 (WallabyII)
  AucStatHistogram, v5.4.4157 (WallabyII)
  AucStatiLevel, v5.4.4157 (WallabyII)
  AucStatPurchased, v5.4.4157 (WallabyII)
  AucStatSales, v5.4.4157.2842
  AucStatSimple, v5.4.4157 (WallabyII)
  AucStatStdDev, v5.4.4157 (WallabyII)
  AucStatWOWEcon, v5.4.4157.2530
  AucUtilAHWindowControl, v5.4.4157.3311
  AucUtilAppraiser, v5.4.4157.2530
  AucUtilAskPrice, v5.4.4157.3175
  AucUtilAutoMagic, v5.4.4157.3142
  AucUtilCompactUI, v5.4.4157.2530
  AucUtilEasyBuyout, v5.4.4157.3583
  AucUtilItemSuggest, v5.4.4157.3108
  AucUtilPriceLevel, v5.4.4157.2545
  AucUtilScanButton, v5.4.4157.2530
  AucUtilScanFinish, v5.4.4157.2530
  AucUtilScanProgress, v5.4.4157.2530
  AucUtilSearchUI, v5.4.4157.3655
  AucUtilSimpleAuction, v5.4.4157.0
  AucUtilVendMarkup, v5.4.4157.2530
  Babylonian, v5.1.DEV.130
  BeanCounter, v5.4.4157 (WallabyII)
  BonusScanner, v4.9
  BrokerBonusScanner, v1.1
  Cartographer, v2.0
  CartographerBattlegrounds, v2.0
  CartographerFoglight, v2.0
  CartographerGroupColors, v2.0
  CartographerGuildPositions, v2.0
  CartographerInstanceLoot, v2.0
  CartographerInstanceMaps, v2.0
  CartographerInstanceNotes, v2.0
  CartographerLookNFeel, v2.0
  CartographerNotes, v2.0
  CartographerPOI, v2.0
  CartographerWaypoints, v2.0
  CartographerZoneInfo, v2.0
  ChatColorResetter, v
  Configator, v5.1.DEV.130
  CurseProfiler, v
  DebugLib, v5.1.DEV.130
  DoTimer, v4.3.1
  ElkBuffBars, v2.2.4-149
  Enchantrix, v5.4.4157 (WallabyII)
  EnchantrixBarker, v5.4.4157 (WallabyII)
  flagRSP, v1.0.8
  GuildMailbox, v0.0.2
  GuildRecruiter, v1
  Informant, v5.4.4157 (WallabyII)
  LibSharedMedia30, v3.0-59
  Omen, v3.0.7
  Outfitter, v4.6
  QuestHelper, v0.106
  sct, v6.2
  sctd, v3.1
  SharedMedia, v3.0
  SlideBar, v5.4.4157 (WallabyII)
  Stubby, v5.4.4157 (WallabyII)
  Titan, v4.2.2.30100 - Revision 239
  TitanAmmo, v4.2.2.30100
  TitanBag, v4.2.2.30100
  TitanClock, v4.2.2.30100
  TitanCoords, v4.2.2.30100
  TitanGoldTracker, v4.2.2.30100
  TitanGuild, v3.6d[QuickFix2]
  TitanLootType, v4.2.2.30100
  TitanPerformance, v4.2.2.30100
  TitanRegen, v4.2.2.30100
  TitanRepair, v4.2.2.30100
  TitanVolume, v4.2.2.30100
  TitanXP, v4.2.2.30100
  WIM, v3.1.1
  XPerl, v3.0.3a
  XPerlArcaneBar, v
  XPerlParty, v
  XPerlPartyPet, v
  XPerlPlayer, v
  XPerlPlayerBuffs, v
  XPerlPlayerPet, v
  XPerlRaidAdmin, v
  XPerlRaidFrames, v
  XPerlRaidHelper, v
  XPerlRaidMonitor, v
  XPerlRaidPets, v
  XPerlTarget, v
  XPerlTargetTarget, v
  XPGetter, v1.6.2
  (ck=ab4)

Please provide any additional information below.
This one seems to happen randomly, and is a Notifications error, I only have about 4 notifications, mostly for showing when my cooldowns fade.