Include header template

[Davey-UK]

What i want is a little direction on how to include the forum header template in all my external php pages(Not in the forum folder).
I know this will be a really simple task, but i have used some code found elsewhere on this forum and it is putting the file up with the header at the top of the page as i want, but any other content i have added under it is gone.

Can someone guide me into what i am doing wrong?

This is the code i was using, or something like

<?php

chdir("./forum");

error_reporting(E_ALL & ~E_NOTICE);

$globaltemplates = array('main');

require_once("./global.php");

eval('print_output("' . fetch_template('header') . '");');
?>

Sorry i couldn't put the script in code tags, but there seems to be a problem when i try to use any of the code options bbcode options, it just sends me to the top of the page and inserts nothing!!

Thanks
Dave