Subreport Calculation field

[Cheshire101]

This is the wierdest thing I have ever seen, can someone please help.
I have a field on a main report that references a calculation on a sub report,
Code:
=IIf([rptDPMOsub].[Report].[HasData],[rptDPMOsub].[Report]![CountSum],0)

** run report and everything looks fine until I start to scroll down and then the same exact cell that once had a number in it changes to "#Name?"
** if I print the report the data is all there, it is only wrong on the preview.

Please help me someone......

[llkhoutx]

#Name means that the field is incorrectly bound, that is bound to a non-existant field.

[RuralGuy]

Do you have all of the Office 2007 Service Packs and HotFixes applied?