print_chooser_row Problem.

[Tuk4]

Hey guys, using 3.6.4 Version. And im trying to add to Users field selecting row.

Now added 2 Hooks:

Hook: useradmin_edit_column1
Added: print_chooser_row('Select Group', 'user[groupid]', 'groups', $user['groupid']);

Hook: userdata_start
Added: $this->validfields['groupid'] = array(TYPE_INT, REQ_NO);

Now when im going to add user - he's using the following sql cmd.
SELECT title, groupsid FROM groups WHERE groupsid....

i get this error because its not the fields i have in my DB, and i have no itention of changing them either, for the reason that i have a whole system running on it, and it will take me ages.
NOW.. my question is how can i select the field he'll choose from.. and update only Groupid on users table..

Im out of ideas..
thanks for the help, appriciated.