Sorry man no idea what is it but bug grubber caught it.
v 2 1 2

1x MonolithDKP\Core.lua:305: attempt to perform arithmetic on field '?' (a nil value)
MonolithDKP\Core.lua:305: in function PurgeDKPHistory' MonolithDKP\init.lua:543: in function OnInitialize'
MonolithDKP\init.lua:184: in function <MonolithDKP\init.lua:166>

Locals:
self =

{
DKPHistory_Update = defined @MonolithDKP\Modules\DKPHistory.lua:257
StartTimer = defined @MonolithDKP\Core.lua:392
StartBidTimer = defined @MonolithDKP\Modules\Bidding.lua:712
ValidateDKPTable_DKP = defined @MonolithDKP\Modules\Validate.lua:66
PurgeDKPHistory = defined @MonolithDKP\Core.lua:277
SortLootTable = defined @MonolithDKP\Modules\LootHistory.lua:11
GetGuildRankGroup = defined @MonolithDKP\Core.lua:206
BroadcastTimer = defined @MonolithDKP\Core.lua:353
ClassGraph = defined @MonolithDKP\Modules\ClassGraph.lua:7
BroadcastStopBidTimer = defined @MonolithDKP\Modules\Bidding.lua:629
ValidateSender = defined @MonolithDKP\Modules\comm.lua:17
CreateBidWindow = defined @MonolithDKP\Modules\Bidding.lua:1108
reset_prev_dkp = defined @MonolithDKP\Modules\ManageEntries.lua:253
Toggle = defined @MonolithDKP\MonolithDKP.lua:24
DKPHistory_Reset = defined @MonolithDKP\Modules\DKPHistory.lua:48
AdjustDKP = defined @MonolithDKP\Modules\AdjustDKP.lua:8
Options = defined @MonolithDKP\Modules\Options.lua:59
AdjustDKPTab_Create = defined @MonolithDKP\Modules\AdjustDKP.lua:187
AutoAward = defined @MonolithDKP\Modules\AutoAward.lua:6
ConfigMenuTabs = defined @MonolithDKP\ConfigMenuTabs.lua:117
LootHistory_Reset = defined @MonolithDKP\Modules\LootHistory.lua:202
DKPModes_Misc = defined @MonolithDKP\Modules\Modes\DKPModesMisc.lua:7
SetTabs = defined @MonolithDKP\ConfigMenuTabs.lua:82
LootTable_Set = defined @MonolithDKP\Modules\BidInterface.lua:21
StartRaidTimer = defined @MonolithDKP\Modules\RaidTimer.lua:135
BidInterface_Toggle = defined @MonolithDKP\Modules\BidInterface.lua:217
OnInitialize = defined @MonolithDKP\init.lua:438
AwardConfirm = defined @MonolithDKP\Modules\Award.lua:292
Table_Search = defined @MonolithDKP\Core.lua:579
SortDKPTable = defined @MonolithDKP\MonolithDKP.lua:167
BidInterface_Create = defined @MonolithDKP\Modules\BidInterface.lua:420
CreateButton = defined @MonolithDKP\Core.lua:342
ToggleDKPModesWindow = defined @MonolithDKP\Modules\DKPModes.lua:6
Commands = {
}
BidTimer = {
}
PurgeLootHistory = defined @MonolithDKP\Core.lua:254
ValidateLootTable = defined @MonolithDKP\Modules\Validate.lua:229
GetMinBid = defined @MonolithDKP\Modules\Bidding.lua:328
ZeroSumBank_Update = defined @MonolithDKP\Modules\ZeroSumBank.lua:69
GetGuildRankIndex = defined @MonolithDKP\Core.lua:162
StopRaidTimer = defined @MonolithDKP\Modules\RaidTimer.lua:100
Sync = {
}
ValidateDKPTable_Final = defined @MonolithDKP\Modules\Validate.lua:135
TableStrFind = defined @MonolithDKP\Core.lua:642
CreateTimer = defined @MonolithDKP\Modules\Bidding.lua:861
CurrItem_Set = defined @MonolithDKP\Modules\BidInterface.lua:346
ZeroSumBank_Create = defined @MonolithDKP\Modules\ZeroSumBank.lua:87
ValidateDKPHistory = defined @Monoli