Error : low framerate in Blackwing descent

[Araldwenn]

When in Blackwing descent, my framerate drop down to 20 ips (instead of 160). The Lua error counter shows error every ms (maybe 100 error/s). All other addons were deactivated while testing. In other raid instances or outside, i don't have any error. I actually use v4.01 beta 1, but the same problem had occured with previous versions.
Playing on French client.

Message: Interface\AddOns\Carbonite\Carbonite.lua:13232: attempt to compare number with nil
Time: 05/02/11 00:09:34
Count: 9979
Stack: Interface\AddOns\Carbonite\Carbonite.lua:13232: in function `IBGM'
Interface\AddOns\Carbonite\Carbonite.lua:21942: in function <Interface\AddOns\Carbonite\Carbonite.lua:21838>

Locals: self = <table> {
 PlX = 0
 LTF = NxMapTip {
 }
 MIMZ = <table> {
 }
 MiF = <table> {
 }
 MMMN = "Interface\Buttons\White8x8"
 Tar = <table> {
 }
 MLY = 0
 ToB = <table> {
 }
 CWUON = 1
 ScW = 0.25
 MMCD = 23
 MDF = <table> {
 }
 CMBG = false
 BAF = 0.25274317582902
 PlF = <unnamed> {
 }
 UTD1 = 0
 EfS = 1
 MMSC = <table> {
 }
 TETA = false
 BAF1 = 1
 BGGB = true
 ArP = 1
 PSX = 0
 MaI3 = 1
 MaS = 0.39920159680639
 IcF = <table> {
 }
 CWUMI = 12190
 MMAN = "Interface\Minimap\MinimapArrow"
 MPXD = 1.8933184957132
 ShU = true
 Con = 2
 TFS2 = <table> {
 }
 BaS = 1
 MMAF = <table> {
 }
 MPYD = 1.4239239972085
 KiS = false
 Zon = 0
 TSF = <unnamed> {
 }
 BGIM = <table> {
 }
 Men = <table> {
 }
 WoA = 0
 Sca = 4
 MISH = <table> {
 }
 H = 141
 MMZT = 0
 MMS1 = 4
 MoE = true
 W = 150
 MMOF = <table> {
 }
 NWU = false
 DRS = 1
 MoD = 180
 Tra1 = <table> {
 }
 BASO = <table> {
 }
 TrM = <table> {
 }
 IcS = 1
 MPY = 1.4239239972085
 MMGI = true
 BGIN = 0
 Si1 = 0.75
 TNUI = 1
 Win1 = <table> {
 }
 DPS1 = 1
 GIMIFN = <table> {
 }
 TeF = <unnamed> {
 }
 ArS = 0.79
 MIPF = <table> {
 }
 MaI = 12190
 DZS = 1
 PIM = <table> {
 }
 GIM = <table> {
 }
 WoH = <table> {
 }
 DPS = 1
 MDO = <table> {
 }
 GIMITI = <table> {
 }
 MaW = 125.84899231752
 LCT = 0
 MMO1 = true
 StS = 1
 Lev = 47
 TrP = <table> {
 }
 TrD = false
 VSD = <table> {
 }
 MMFS = 0.4
 Ind1 = 1
 Scr2 = false
 Tic = 9979
 MMZC = false
 PRZX = 0
 PlD = 122.58038414831
 BaA = 0.25274317582902
 MMGUD = 1
 SDW = 0.25
 BAT = 0.25274317582902
 InI = 12190
 PRZY = 0
 MaH = 109.31428923675
 MMM = <table> {
 }
 Gui = <table> {
 }
 TiF1 = <table> {
 }
 RMI = 12190
 INIF = <table> {
 }
 GOp = <table> {
 }
 MPX = 1.8933184957132
 LTFS = <table> {
 }
 MiB = 6
 MLX = 0
 LOp = <table> {
 }
 UTD = 0
 PSCT = 420608.895
 StT = 0
 ISF1 = <table> {
 }
 Dat = <table> {
 }
 ScD = 4
 MISW = <table> {
 }
 MISM = <table> {
 }
 PaX = 0
 TiH = 0
 MMAD = 0
 MMS = <table> {
 }
 PSY = 0
 CuO = <table> {
 }
 CuO1 = false
 WHC = <table> {
 }
 DAS = 0.1
 PlY = 0
 Frm = <unnamed> {
 }
 CoF = <table> {
 }
 PlS = 0
 PLD = 122.58038414831
 INS = 1
}
maI = nil
(*temporary) = nil
(*temporary) = "attempt to compare number with nil"