500 Internal Server Error because of a line of code in system/core/CodeIgniter.php

[eluser]brianbabu[/eluser]
Fatal error: Call to undefined method CI_Session::all_userdata() in D:\PLESKVHOSTS\vhosts\pdocricket.com\httpdocs\TestCMS\application\controllers\dashboard.php on line 23

This is what my dashboard does:

Code:

function __construct()
{
  parent::__construct();
  $this->is_logged_in();
  $this->load->model('Login_model');
  $this->load->model('Settings_model');
  $this->load->model('Category_model');
  $this->load->model('Page_model');
  $this->load->model('Post_model');

}

function is_logged_in()
{
  if($this->session->userdata('is_logged_in')!=TRUE)
  {
   redirect("admin");
  }
}

public function index()
{
  $users_id=$this->session->userdata('users_id');
  
  $data=array(
   "username"    =>  $this->Login_model->userinfobyid('users_username', $users_id),
   "avatar"    =>  $this->Login_model->userinfobyid('users_avatar', $users_id),
   "name"     =>  $this->Login_model->userinfobyid('users_name', $users_id),
   "pagetitle"   => 'Dashboard',
   "dynamic_loading"  => $this->Settings_model->fetchsetting("site_dynamic_loading"),
   "categories"  => $this->allcategories()
  );
  $data['latestposts']=$this->Post_model->latestpost("",5);
  $data['latestpages']=$this->Page_model->latestpage(5);
  $this->load->view('admin/dashboard', $data);
}