VDF16 and CrystalXI. Everything working fine for months, then with no changes from us, client gets an Unhandled Program Error - Com Object Method Invocation Error - Unknown Database connector error. (Error 4399)
Reinstalling Crystal (doing a Repair) did not fix.
I'd say from the message it's an issue with the connectivity kit. May be check that driver is located where it should be. I assume you are using the embedded database?