Chat Scrolling

[Amrash]

with both classic and IM style options I get the following when I try to Mousewheel scroll in the chat window

Message: Interface\AddOns\nUI\Integration\nUI_ChatFrame.lua:289: attempt to compare number with nil
Time: 09/23/10 14:47:17
Count: 26
Stack: Interface\AddOns\nUI\Integration\nUI_ChatFrame.lua:289: in function <Interface\AddOns\nUI\Integration\nUI_ChatFrame.lua:288>

Locals: (*temporary) = nil
(*temporary) = nil
(*temporary) = "attempt to compare number with nil"
cframe = ChatFrame1 {
0 = <userdata>
flashTimer = 0.2494690977037
isInitialized = 1
is_chat_frame = true
tellTimer = 27215.72
hasBeenFaded = true
resizeButton = ChatFrame1ResizeButton {
}
buttonFrame = ChatFrame1ButtonFrame {
}
buttons_visible = true
oldAlpha = 0
channelList = <table> {
}
mouseOutTime = 0
clickAnywhereButton = ChatFrame1ClickAnywhereButton {
}
isDocked = 1
mouseInTime = 0
editBox = ChatFrame1EditBox {
}
showButtons = <function> defined @Interface\AddOns\nUI\Integration\nUI_ChatFrame.lua:256
isLocked = 1
name = "General"
buttonSide = "RIGHT"
isStaticDocked = true
zoneChannelList = <table> {
}
defaultLanguage = "Common"
messageTypeList = <table> {
}
}

apart from nUI I have Recount, Omen and HealBot, but it occurs without other addons also.