ติดต่อฐานข้อมูลระหว่าง PHP กับ SQLSERVER 2008 ไม่ได้ครับ

<?PHP
header("Content-type: text/html; charset=UTF-8");
require_once "config.php";
require_once "class_connection.php";
$cn = new ClassConnection();

  $x = $cn->setConfigFile("config_base.php");
  $cn->connect();

  $query = "SELECT  *  FROM  DBO.PERSON";
  $result = $cn -> Query($query); 
  $numrows =$cn -> Numrows($result); 
  $row= & $cn -> GetData($result);
		
  $cn->Close();
?>

         <?PHP 
             $DATABASE_TYPE= "MSSQL";
	     $DATABASE_SERVER="NAMESERVER";

	    $DATABASE_PROTOCOL= "";
	   $DATABASE_PORT= "";
	   $DATABASE_DB= "NAMEDATABASE";
            $DATABASE_USER= "sde";
           $DATABASE_PASSWORD= "abcd";
           $connection_string = "DRIVER={SQL Server};SERVER=$DATABASE_SERVER;DATABASE=$DATABASE_DB"; 
								
?>