Lost display of custom field in upgrade to 2.7

I upgraded my WordPressMU to 2.7 yesterday and all was simple and easy. However, I had a custom field in one of my blogs called Attribution with Authors Name as the value (I know I should just use Author meta, but long story). It all appears to be there in the backend, because it shows up in the custom field area with SEO, etc. However it is not showing up in my theme? I did a little customization to implement the display of the Attribution meta, but it was displaying fine in 2.6? Was there some sort of small tweak in 2.7 loop? Here is what I have in my single.php …

<div class="meta">
      <?php $attribution = get_post_meta
         ($post->ID, 'Attribution', $single = true);
          if($attribution !== '') echo '<em>Contributed by</em>: ' . $attribution;
       ?>
</div>

here is my blog: wordpress.esc.edu/writingcenter/