CodeIgniter ile download işlemi sorun yaşıyorum

 
 header("Pragma: public"); 
         header("Expires: 0"); 
         header("Cache-Control: must-revalidate, post-check=0, pre-check=0");  
         header("Content-Type: application/force-download"); 
         header("Content-Type: application/octet-stream"); 
         header("Content-Type: application/download"); 
         header("Content-Disposition: attachment;filename=".$_GET['file']); 
         header("Content-Transfer-Encoding: binary ");