Not Finding My Model

[eluser]hitraj47[/eluser]
[quote author="deep_sheera" date="1338531590"] $data['pages_list'] = $this->page_model->get_page_list_admin(); ..... try to call another function and then check is really page_model not load here or is there any other problem in that function ..[/quote]

I made a function called test() in my page_model.php:

Code:

public function test() {
$test = 'test';
return $test;
}

Then I assigned $data['pages_list'] to $this->page_model->test(); and I got the same error, this time PHP is saying Fatal error: Call to a member function test() on a non-object

Then when I changed it back to

Code:

$data['pages_list'] = $this->page_model->get_page_list_admin();

I get the same error as before, with PHP saying: Fatal error: Call to a member function get_page_list_admin() on a non-object

I even changed it to one of the functions that already existed in the page_model that works in my Page controller and I still get the same error.

EDIT:
Wow I just fixed it... In my admin.php controller I had:

Code:

public function __construct() {
  parent::__construct();
  $this->load->helper('form');
  $this->load->library('form_validation');
  $this->load->library('template');
$this->load->model('page_model');
}

As you can see I load the page_model last... I moved that up to the top so now it says:

Code:

public function __construct() {
  parent::__construct();
  $this->load->model('page_model'); // page model loads first
  $this->load->helper('form');
  $this->load->library('form_validation');
  $this->load->library('template');
}

This fixed the errors... I don't know why this worked, can someone explain it? Should models/helpers and libraries etc that are loaded in the constructor be loaded in a certain order?