Lost function during upgrade to call latest posts with thumbnails

I’ve just upgraded to 3.04, but didn’t backup my functions.php before doing so. I’m using a child theme of Twenty Ten and think I have lost a custom function that displays my latest posts (with a thumbnail) on the homepage. This is the code I’ve been using to display the latest posts:

<div id="homepage">
<div class="post">
<h2>NEW</h2>
<?php
$latestposts = get_posts('numberposts=10');
foreach($latestposts as $post) :
   setup_postdata($post);
?>
<div id="hplist">
<ul><li>
<div class="thumb"><a href="<?php the_permalink(); ?>"><?php dp_attachment_image($post->ID, 'thumbnail', 'alt="' . $post->post_title . '"'); ?></a></div>
<a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
<?php the_excerpt(); ?></li></ul>
</div><!-- end hplist -->
<?php endforeach; ?>
</div<!-- end post-->
</div><!-- end homepage -->

I think I’m missing a function that uses dp_attachment_image

I’ve been searching the web for a while now but can’t find a solution so I’m hoping someone in the forum can offer some assistance.