It looks like it isn't adding the hidden form identifier it uses as the trigger. You can either add this to your form:
<input type="hidden" name="MM_insert" value="form1">
or update the server behavior and change the trigger to use your submit button. I'll get it fixed to automatically add the hidden form element in the next build.
You could also use the MySQLi insert record server behavior, which has you set the trigger on application and wouldn't have this issue.