SalesForce.com error Database Connector Error: Database Vendor Code: -1

Getting the error (Database Connector Error: '' [Database Vendor Code: -1 ]'') when using RUN TIME cystal reports, but no error when running desktop version. Just happening on one particular report - that worked last month. Other SFDC reports work, so it has do be something with this report WITH runtime only.

Did my handy Google searches and coming up empty with this. Anyone run into this before? Suggestions on how to debug?
Chris