multiUpload library problem - fatal error

Code:
public function upload()

  {



        $config['upload_path'] = './images/products/'; // server directory

        $config['allowed_types'] = 'gif|jpg|png|pdf'; // by extension, will check for whether it is an image

        

        $this->load->library('upload', $config);

        $this->load->library('Multi_upload');

    

        $files = $this->multi_upload->go_upload();

        

        if ( ! $files )        

        {

            $error = array('error' => $this->upload->display_errors());

   print_r($error);

            //$this->load->view('dashboard/main_menu/dashboard_hmenu_view', $error);

        }    

        else

        {

            $data = array('dashboard/dashboard_mainpage_view' => $files);

            $this->load->view('upload_success', $data);

        }

   

  }