[Plugin: Facebook] Headers already sent error

On my website (non-wordpress pages) I have a recent posts feed showing. That part works fine, but I am getting the error

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/bluepand/public_html/index.php:25) in /home/bluepand/public_html/blog/wp-content/plugins/facebook/includes/facebook-php-sdk/facebook.php on line 39

The code I use to grab the recent posts is

<?php
require('blog/wp-blog-header.php');
?>

<h3>Latest articles</h3>
				<div>
					<?php query_posts('showposts=3'); ?>
<?php while (have_posts()) : the_post(); ?>
<p><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title(); ?>"><?php the_title(); ?></a></p>
<?php endwhile;?>
				</div>

Any ideas on how to solve this? You can view the problem at http://blue-panda.co.uk (right bar of index page)

http://wordpress.org/extend/plugins/facebook/