David, what AERROR() are you getting when you try to update the vfp table via vfp ODBC. I understand that you are running a stored procedure. Is the stored procedure in the backend. I had a similiar problem. I'm using the basic Tastrade stored procedure newid() to get a unique id. Problem I had was that before the id was updated by the backend I would get an error that the id could not be null. I recently updated the ODBC drive with 6.0 and it worked.
Michael Garcia