First attempt a programming with VB - problem

[markross]

I need to write a script that will access VB variables, so I am starting out with some basic practice scripts to get the hang of it. However I am encountering a problem at the first stage. I have made a simple script as follows:

<?php

require_once('./global.php');

if ($show['guest'])
	echo "you're not logged in";

else
	echo "you are logged in";


?>

This script works fine if I'm logged in. However if I'm not logged in I get the following error:

"Unable to add cookies, header already sent.
File: /var/www/vhosts/urban-gorilla.co.uk/httpdocs/community/test.php
Line: 10"

Can anyone suggest why this might be happening?

Thanks

Mark