[Solved] Error trying to deploy HMVC with CI (working with nettuts-Tutorial)

[eluser]cmh24[/eluser]
Hey everybody,

I get an error-message while trying to deploy HMVC (5.4) with CI 2.03. I followed the nettuts-Tutorial, it's a bit outdated, so I made the necessary adjustments. Now I'm halfway through and now I encouter a problem.
By the way here is the link to the tutorial.

net.tutsplus.com/tutorials/php/hvmc-an-introduction-and-application/

The error message says.
A PHP Error was encountered

Severity: Notice

Message: Undefined property: Login::$session

Filename: controllers/login.php

Line Number: 34

and

Fatal error: Call to a member function userdata() on a non-object in C:\xampp\htdocs\hmvc-example\application\modules\login\controllers\login.php on line 34

This is the beginning of my login-controller

Code:

<?php

class Login extends CI_Controller
{

function index()
{
  $data['main_content'] = 'login_form';
  $this->load->view('includes/template', $data);  
}

function validate_credentials()
{  
  $this->load->model('membership_model');
  $query = $this->membership_model->validate();
  
  if($query) // if the user's credentials validated...
  {
   $data = array(
    'username' => $this->input->post('username'),
    'is_logged_in' => true
   );
   $this->session->set_userdata($data);
   redirect('site/members_area');
  }
  else // incorrect username or password
  {
   $this->index();
  }
}

function is_logged_in()
{
  $is_logged_in = $this->session->userdata('is_logged_in');
  if(!isset($is_logged_in) || $is_logged_in != true)
  {
   echo 'You do not have permission to access this page. <a href="../login">Login</a>';
   die();  
   //$this->load->view('login_form');
  }  
}

This is the part that makes the problem.

Code:

$is_logged_in = $this->session->userdata('is_logged_in');

This is line 34.

It happens when I try to login and enter the members_area. Here is the site-controller.

Code:

<?php

class Site extends CI_Controller
{
function __construct()
{
  parent::__construct();
  modules::run('login/is_logged_in');
}

function members_area()
{
  $this->load->view('logged_in_area');
}

function another_page() // just for sample
{
  echo 'good. you are logged in.';
}

}

The session library is autoloaded and a encryption key has been set. So, I am dependent on your help!

Thanks in advance!
Max