Mengatasi Session Error di Codeigniter

Tempatkan script ini di Controller :

header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
header("Cache-Control: no-store, no-cache, must-revalidate")
 header("Cache-Control: post-check=0, pre-check=0", false);
  header("Pragma: no-cache");
             $this->load->view('_header', $datarok);
            $this->load->view('form_observe', $datae);
            $this->load->view('_footer', $datae);