What steps will reproduce the problem?
1. Be in a raid
2. Be the lootmaster
3. Open boss corpse for looting

What is the expected output? What do you see instead?
Just the lootmenu, a error popped up (and the lootmenu)

What version of the product are you using?
  XLoot, v0.91.1
  XLootGroup, v0.61
  XLootMaster, v0.81
  XLootMonitor, v0.71
  (and in case ArkAutoLootBoP, v1.00

Do you have an error log of what happened?
Date: 2011-03-11 00:09:29
ID: 4
Error occured in: Global
Count: 1
Message: ..\AddOns\XLootMaster\XLootMaster.lua line 322:
   Usage: GetLootSlotInfo(slot)
Debug:
   (tail call): ?
   (tail call): ?
   Ace2\AceEvent-2.0\AceEvent-2.0.lua:299 TriggerEvent()
   Ace2\AceEvent-2.0\AceEvent-2.0.lua:910
      Ace2\AceEvent-2.0\AceEvent-2.0.lua:903
   [C]: LootSlot()
   ArkAutoLootBoP\ArkAutoLootBoP.lua:33
      ArkAutoLootBoP\ArkAutoLootBoP.lua:11

Please provide any additional information below.
Might be this is related to ArkAutoLootBoP running along.
Dunno which one is the evil one in this case.