PHP pdo azure problem

Question

hello !

i got an application that i'm wrote.

the application works great localy on iis 7 .. and when i am uploading that to azure.. something bad happend..!

i tested few script and found out that the problem is pdo extends..

what is wrong with the extend in azure server??? (working good on local pc....) 

<?php 


 class Database extends PDO { 

       private static $instance;

       public static function  getInstance() {        if(self::$instance === null) {            self::$instance = new Database();        }        return self::$instance;    }

/////////////////////////////

 private function __clone() { }

/////////////////////////////

 public function  __destruct(){$instance = null;}

/////////////////////////////
    public function __construct(){ 
        
        parent::__construct("string!!");     
         
    } //end of public function __construct
     
  

/////////////////////////////
/////////////////////////////


}

?>

and in the php.ini file:

[PHP_PDO_SQLSRV_53_TS]
extension=php_pdo_sqlsrv_53_ts.dll
[PHP_SQLSRV_53_TS]
extension=php_sqlsrv_53_ts.dll

what's wrong ?

thanks!

edit: every page that using db class will return 500 Internal Server Error