CHDIR question

[Boofo]

I have this piece of code in my chat.php file which is in the forums/chat directory. When a guest tries to view the chat they get a no permission error like it is supposed to do. But for some reason, the header takes up half the page and it doesn't show the header image. It is looking for the header in the chat/images directory which doesn't exist. How can I avoid that when they get a no permission error?

PHP Code:

 // ######################### REQUIRE BACK-END ############################
chdir('./../');
require_once('./global.php');
// ######################## START MAIN SCRIPT ############################
// Guests cannot access RealChat Rooms
if ($vbulletin->userinfo['userid'] == '0')
{
 print_no_permission();
}