Strange issue with validation libraries

[eluser]daweb[/eluser]
This is my external file:

Code:

<?php
    $rules['username'] = 'trim|required|min_length[5]|max_length[200]';
    $rules['password'] = 'trim|required|min_length[5]|max_length[200]|callback_check_login';
    $this->validation->set_rules($rules);

    $fields['username'] = $this->lang->line('formUsername');
    $fields['password'] = $this->lang->line('formPassword');
    $this->validation->set_fields($fields);
?>

It works fine in all my controllers (bambooinvoices dictat :-))