This error appears as soon as i've log

Date 2010-08-09 012209
ID 1
Error occured in Global
Count 1
Message ...ceAddOnsWoWPro_LevelingWoWPro_Leveling_Parser.lua line 512
attempt to concatenate a nil value
Debug
(tail call)
[C]
...ceAddOnsWoWPro_LevelingWoWPro_Leveling_Parser.lua512 UpdateQuestTracker()
...ceAddOnsWoWPro_LevelingWoWPro_Leveling_Parser.lua299 EventHandler()
WoWProWoWPro_Broker.lua140
WoWProWoWPro_Broker.lua121
AddOns
Swatter, v5.8.4723 (CreepyKangaroo)
AckisRecipeList, vv2.0
ACP, v3.3.4
Atlas, v1.16.1
AtlasBattlegrounds, v1.16.1
AtlasDungeonLocs, v1.16.1
AtlasOutdoorRaids, v1.16.1
AtlasTransportation, v1.16.1
AtlasLoot, vv5.11.03a
AtlasLootFu, vv5.11.03a
AtlasQuest, v4.4.3
AucAdvanced, v5.8.4723 (CreepyKangaroo)
AucFilterBasic, v5.8.4723 (CreepyKangaroo)
AucFilterOutlier, v5.8.4723.2531
AucMatchUndercut, v5.8.4723.2531
AucStatHistogram, v5.8.4723 (CreepyKangaroo)
AucStatiLevel, v5.8.4723 (CreepyKangaroo)
AucStatPurchased, v5.8.4723 (CreepyKangaroo)
AucStatSales, v5.8.4723.2842
AucStatSimple, v5.8.4723 (CreepyKangaroo)
AucStatStdDev, v5.8.4723 (CreepyKangaroo)
AucStatWOWEcon, v5.8.4723.2530
AucUtilAHWindowControl, v5.8.4723.3311
AucUtilAppraiser, v5.8.4723.2530
AucUtilAskPrice, v5.8.4723.3175
AucUtilAutoMagic, v5.8.4723.3142
AucUtilCompactUI, v5.8.4723.2530
AucUtilEasyBuyout, v5.8.4723.3583
AucUtilFixAH, v5.8.4723 (CreepyKangaroo)
AucUtilGlypher, v5.8.4723.2545
AucUtilItemSuggest, v5.8.4723.3108
AucUtilPriceLevel, v5.8.4723.2545
AucUtilScanButton, v5.8.4723.2530
AucUtilScanFinish, v5.8.4723.3576
AucUtilScanProgress, v5.8.4723.2530
AucUtilScanStart, v5.8.4723.2530
AucUtilSearchUI, v5.8.4723.3655
AucUtilSimpleAuction, v5.8.4723.4546
AucUtilVendMarkup, v5.8.4723.2530
BeanCounter, v5.8.4723 (CreepyKangaroo)
DBMCore, v
EasySerum, v1.06
Enchantrix, v5.8.4723 (CreepyKangaroo)
EnchantrixBarker, v5.8.4723 (CreepyKangaroo)
GatherMate, vv1.23
GatherMateSharing, v1.3
Informant, v5.8.4723 (CreepyKangaroo)
LilSparkysWorkshop, v
QuestHelper, v1.4.0
Recount, v
SlideBar, v5.8.4723 (CreepyKangaroo)
Stubby, v5.8.4723 (CreepyKangaroo)
TomTom, vwowirevision
WoWPro, v1.0.0
WoWProLeveling, v1.0.0
BlizRuntimeLib_enUS v3.3.5.30300 eu
(ck=731)

Alright. I think I see what went wrong, looks like the quest does not have any objectives but is in the log, but it shows a nil value when you try to get the objectives. Will fix, thanks for the report.

Fix uploaded, needs testing, will be in next major release.