Updating the cache so all user ranks appear?

[drew010]

PHP Code:

    if ($foruminfo['forumid'] == 38)
    {
        require_once(DIR . '/includes/functions_user.php');
        require_once(DIR . '/includes/functions_databuild.php');
        $userdm =& datamanager_init('User', $vbulletin, ERRTYPE_SILENT);
        $user = $db->query_first("SELECT * FROM " . TABLE_PREFIX . "user WHERE `userid`=".$db->sql_prepare($vbulletin->userinfo['userid']));
        $userdm->set_existing($user);    
        $splitvotes = explode('|||', $pollinfo['votes']);
        if ($vbulletin->GPC['optionnumber'] == 1) 
        {
            $splitvotes[0] += 1;
        }
        if ($splitvotes[0] >= 1)
        {                        
            if ((!in_array('9', explode(',', $user['membergroupids']))) && ($user['usergroupid'] != '9'))
            {
                if ($user['usergroupid'] == '4') 
                {
                    $user['usergroupid'] = '9';
                } else {
                    $membergroups = explode(',', $user['membergroupids']);
                    $membergroups[] = '9';
                    $user['membergroupids'] = implode(',', $membergroups);
                }
                $userdm->set('usergroupid', $user['usergroupid']);
                $userdm->set('membergroupids', $user['membergroupids']);
                $userdm->save();
            } 
        }
    } 


Basically if it's in forum 38, and the user get's => 1 vote, they get promoted to group 9. It updates in phpMyAdmin, so I know it works, but in order to get the rank to appear I have to hit 'Update User Ranks and Titles'. I tried taking the relevant part of that process from misc.php and using it to my own advantage, but to no avail; I simply can NOT get it to update. Any help appreciated!