Problem with a script after upgrading to mySQL 5 and PHP 5

[Cloud Strife]

I have one last script thats causing me troubles. I get this error:-

Fatal error: Cannot use object of type vB_Session as array in et/home/siteupload/public_html/forums/showthread.php(1953) : eval()'d code on line 33

From this line of code:-

PHP Code:

    while ($user = $db->fetch_array($result))
    {
            array_push($viewers, "<a target=\"_blank\" href=\"member.php?".$vbulletin->session['sessionurl'] . "u=".$user['userid'] . "\">" . htmlspecialchars($user['username']) .    "</a>");
    } 


Thanks for the help