php newbie : non-object problem

Hi,
I have installed & configured (as per the instructions specified by
Gforge installation document ) Postgresql - 7.2.4, apache 1.3.28, php 4.3.3
with Gforge 3.0. All my configuration steps passed without any error.

But when I am trying to access index.php (/var/www/gforge-3.0/www/index.php)
it gives the error message...

Fatal error: Call to a member function on a non-object in
/var/www/gforge-3.0/www/index.php on line 19

There is no information in the error_log, access_log for apache and also no
error in the Postgres log.

This is the source code for index.php (provided by
forge) -----------------------------------------------------------
<?php
/**
*
* SourceForge Front Page
*
* SourceForge: Breaking Down the Barriers to Open Source Development
* Copyright 1999-2001 (c) VA Linux Systems
* http://sourceforge.net
*
* @version $Id: index.php.patched,v 1.1.2.1 2002/11/30 09:57:57 cbayle
Exp $
*
*/

require_once('www/include/pre.php'); // Initial db and session library,
opens session
require_once('www/news/news_utils.php');
require_once('common/forum/Forum.class');
require_once('www/include/features_boxes.php');

$HTML->header(array('title'=>$Language->getText('index','welcome'),'pagename
'=>'home')); //This is line 19

// Main page content is now themeable;
// Default is index_std.php;
include ( $HTML->getRootIndex() );

$HTML->footer(array());
?>
-------------------------------------------------- until here
Please help me. Thanks in advance,

Regards,
Kalyan.