I'm frequently getting an overflow error on this line of code

Set FindCell = .Cells.Find(What:=myPattern, _
After:=.Cells(.Cells.Count), _
lookat:=xlWhole, _
searchorder:=xlByRows, _
SearchDirection:=xlNext, _
MatchCase:=False, _
SearchFormat:=False)


can someone help me figure out why. I've recently moved to Office 2007 and
am seeing it there when I didn't see it in Office 2003.

Thanks,
Barb Reinhardt