After I followed Craigs' article to skip the error, Crystal 8.5 viewer seems to work fine directly with VFP. Thanks for Craigs' advice.

My app is a n-tier client/server app. I dropped the viewer into frmFormcustom class to create a form which is only used as the VFP client to view the rpt output. All rpt files are generated by a VFP process running at server. Since major processing logic has been written in VFP, I simply pulled all necessary data from SQL server and let VFP to run on local cursors. It produces one or two temp tables as the result which will be used by COM object calling Crytsal report to generate output in rpt format. With subreport feature in Crytsal report, I can produce the report format which simply cannot be done by VFP build-in report writer. As long as the VFP process is running on the same box as SQL server, the response time has been quite acceptable even with a complex report with tens of thousands of records pulled from SQL DB.