Having Issues Connecting to Microsoft SQL Server Express (2008) from PHP

<?php
    include('adodb5/adodb.inc.php');
    $db =& ADONewConnection('odbc_mssql');
    $db->debug = true;
    $dsn = "Driver={SQL Server};Server=ozmodiar;Database=bggs;";
    $db->Connect($dsn,'user','password');
    $rs = $db->Execute('select * from admin_users');
    print "<pre>";
    print_r($rs->GetRows());
    print "</pre>";
?>