404 Page Broken

Something is wrong with my 404 page: http://www.affinnova.com/gravy for example. The code for the 404 page is simply this:

<?php $not_found_page_id = get_theme_options( "affinova", "page_options" , "404" ) ; ?>
<?php if ( $post = get_post( $not_found_page_id ) ){  ?>
<article class="cf">
	<h1 class="title"><?php echo $post->post_title; ?></h1>
	<div class="post-content"><?php echo apply_filters('the_content', $post->post_content ); ?></div>
</article>
<?php } else { ?>
<article class="cf">
	<h1 class="title">Page not found</h1>
	<div class="post-content"><p>Sorry, we cannot find what you are looking for</p></div>
</article>
<?php }

What could be the problem?