Php Site admin paneli sorunu. Yardım!

<?php
/* 
 * Generated by CRUDigniter v3.2 
 * www.crudigniter.com
 */
 
class Dashboard extends CI_Controller{
    function __construct()
    {
        parent::__construct();
        $this->load->model('Site_user_model');
         $userid =  $this->session->userdata('userid');
        if(empty($userid))     
        {    
        redirect('login');
        }
    }
    function index()
    {
        $data['site_user'] = $this->Site_user_model->get_site_user(1);
        $data['_view'] = 'dashboard';
        $this->load->view('layouts/main',$data);
    }
}

function get_active_user(){
    $t = &get_instance();
    $user = $t->session->userdata("user");
    if($user)
    return $user;
    else
    return false;
  }

class Dashboard extends CI_Controller{
    function __construct()
    {
        parent::__construct();
        $this->load->model('Site_user_model');
   if(!get_active_user()){
      redirect(base_url("login"));
    }