I’ve not had that kind of trouble before – so maybe something else is going on here.
You say you copied the report? Is there any chance that there used to be more than one data provider? If so, did you purge the extra DP(s) before you deleted them? If not, they may still be there, complicating your life.
You could try checking in the BOB’s Downloads forum, and use a utility to copy your data provider to a new report, and see if the problem goes away.
Anita Craig 
(BOB member since 2002-06-17)