Session problem

[eluser]MWebber[/eluser]
Hi,
In my logout controller i receive this error:

Code:

Severity: Warning

Message: Cannot modify header information - headers already sent by (output started at /home/xxx/xxx/xxx/system/libraries/Exceptions.php:166)

Filename: libraries/Session.php

Line Number: 662

i receive it when i execute the sess_destroy. is this bug or the problem is in my application
(i have checked all files for white spaces).

logout controller:

Code:

<?php
class Logout extends MY_Controller
{
    function index()
    {
        $this->session->sess_destroy();
    }
}