See Mike's response for more information.

The C5 is a GPF. VFP grabs the error from the OS before Dr. Watson can get it.

>I was under the impression that the C..05 error is an unhandled exception error, that something happens that throws an error that COULD be caught if only there was a cooresponding CATCH statement in the C code. I've had C..05 errors while performing a SQL select that performs a read operation on a memo field when certain records in the source recordset contain corrupted memo field pointers.
>
>I'm not exactly sure on the C..FD error...