phpbb custom page... BLANK

[Zugzwangle]

I have copy and pasted the code, from this webpage... editing only the name of a file... http://www.phpbb.com/kb/article/add-a-new-custom-page-to-phpbb

and it gives me a blank page, even after inserting the sample data, in the 'schedule.html'. I'm suprised to be halted from progress at the first hurdle. Would anyone be able to help?

<?php
define('IN_PHPBB', true);
$phpbb_root_path = (defined('PHPBB_ROOT_PATH')) ? PHPBB_ROOT_PATH : './';
$phpEx = substr(strrchr(__FILE__, '.'), 1);
include($phpbb_root_path . 'common.' . $phpEx);

// Start session management
$user->session_begin();
$auth->acl($user->data);
$user->setup();

page_header('Schedule Page');

$template->set_filenames(array(
    'body' => 'schedule.html',
));

make_jumpbox(append_sid("{$phpbb_root_path}viewforum.$phpEx"));
page_footer();
?>