[AccessD] SourceObject

After converting an Access 97 database to Access XP, I am encountering the following problem:

A report ("rptUnionProposal") contains a subreport ("subrptUPOHP").  There are several versions of this subreport (e.g., "subrptUPOHP", "subrptUPOHPA", "subrptUPOHPB", etc.).  In the Report Open event, I set the SourceObject for the subreport as follows:

Me.subrptUPOHP.SourceObject = "report.subrptUPOHP" & strOption

This has worked fine in Access 97.  In Access XP, however, I receive the error message - 3011 - the Microsoft Jet database could not find object "~sq_drptUnionProposal~sq_dsubrptUPOHP"

Any ideas on what's happening?

Thanks,
Barb Ryan