Crystal Error 506 in Version 4.5

[beattiel]

I'm calling a report from VB6, and randomly get the error 506(or 20506 returned to VB) with the description "Invalid File Number."

According to my trusty error code definitions, this means:

&quot;You have tried to set an Nth file name and the file number you specified is out of the existing range. 0<= filen < N files.&quot;

Can anyone help me translate this error description into English, and suggest possible causes? (The report shows some data direct from my Oracle8 DB, some data passed in through formulas, using ReportFileName to point to the .rpt file and ReplaceSelectionFormula to set up my selection criteria.)

Thanks,
Lesley