Ok... this is where a process of methodical elimination becomes useful. Once exhausting all probable avenues you have to go back to basic and start from the beginning.

I would try tacking the following things :

1. Is the ODBC DSN created properly?
2. Have you run the "Test" on the ODBC and it said Successful?
3. Can you at least READ records from the database?
4. Test to see what the RecordCount is for your clause first
5. Reduce your update to only a single field

Somewhere along that line you should encounter a problem which shows that the error you are getting is a side-effect of the real problem.