I encountered one instance of this error message while I was copying and inserting a worksheet. Changing my procedure to inserting a blank worksheet then copying the usedrange of the source worksheet eliminated this problem.
From researching the error message, there seems to be multiple problems that generate this message.
I'm experiencing this problem in XL2007. The macro runs fine in 2000/2003, but runs afoul of this "error" in 2007. My procedures do copy worksheets, but I've always used the method pbornemeier suggested. Is there any way around this error via VBA?