It would be nice if you could post the entire subprocedure so we could get a bit of the context; also, maybe show the report_open event to see how you use the openargs.
I use a different method to create PDFs: I define a public variable (lets say Public lngClientID as long), then I set a recordset that contains all the ClientIDs I want to include and loop in there making lngClientID =rst("ClientID") and docmd.outputto acOutputReport,"rptMyReport",acFormatPDF..... The report uses as recordsource a query that has a custom function that limits the records to just the current ID in the loop:
Code:
Public Function vcSelectedCliendID() as Long
vcSelectedCliendID=lngClientID 'the public variable I change inside the loop
End Function
Cheers,
Vlad