Question about PM user when add repuation

[slowhand.chen]

I add plugin on "reputation_add_complete"
now, the user is receive this PM,but narbar (pm Unread ,Total ) is not update.
please help.

the code is

PHP Code:

if ($score < 0)
{ 
    // Construct the message subject 
    $subject = $vbphrase['q_pm_on_decrease_repution_message_subject'];
    // Construct the message text 
    $message = construct_phrase(
    $vbphrase['q_pm_on_decrease_repution_message_text'], 
    $userinfo['username'],
    $postid,
    $db->escape_string(fetch_censored_text($vbulletin->GPC['reason']))      
      ); 

    // Init the PM datamanager 
    $pm =& datamanager_init('PM', $vbulletin, ERRTYPE_ARRAY); 

    // Fill in the blanks 
    $pm->set('fromuserid', 1); 
    $pm->set('fromusername', 'admin'); 
    $pm->set('title', $subject); 
    $pm->set('message', $message); 
    $pm->set_recipients($userinfo['username'], $userinfo['permissions']); 
    $pm->set('dateline', TIMENOW ); 


    // Send the PM 
    if (empty($pm->errors)) 
    { 
        // There are no errors, so send the PM 
        $pm->save(); 
    }
}