Output Class question!

[eluser]bogdan3l[/eluser]
Hello!

I have a problem with the output class.
I've tried the example from (http://ellislab.com/codeigniter/user-gui...utput.html):

$this->output->set_header("HTTP/1.0 200 OK");
$this->output->set_header("HTTP/1.1 200 OK");
$this->output->set_header('Last-Modified: '.gmdate('D, d M Y H:i', $last_update).' GMT');
$this->output->set_header("Cache-Control: no-store, no-cache, must-revalidate");
$this->output->set_header("Cache-Control: post-check=0, pre-check=0");
$this->output->set_header("Pragma: no-cache");

and i get an error from $last_update variable.

How should i set the $last_update? An example or something would be great.

Thanks a lot!