Are there any solution for this. I have the same problem too.
The key value from the main table join writes to the relational table as it should, but the options form field value does not. It writes the value 0 to the database, not the value from the form field.
I'm attaching my page.
Live URL here: Kunde_skjema.php
I also get the attached error message after I have picked the "Go to" file. Deleting the winfile cache does not help.