DB_Dataobject insert() returning null

Hi, I have a DataObject for the table shown below. My ini file lists a key column, so I believe this should work. Yet the value of $record_id is NULL. CREATE TABLE subscriber ( user_id int(10) unsigned NOT NULL auto_increment, username varchar(45) NOT NULL default '', password varchar(32) NOT NULL default '', firstname varchar(45) NOT NULL default '', lastname varchar(45) NOT NULL default '', ... PRIMARY KEY (user_id) ) TYPE=MyISAM; And the code:

    $s =& DB_DataObject::factory('Subscriber');
    $s->setRowValues($_POST);
    $s->role = 1; // Basic user
    $record_id = $s->insert();

Any ideas why? Thanks, Peter -- Maple Design - quality web design and programming http://www.mapledesign.co.uk