Index: wp-includes/post.php
===================================================================
--- wp-includes/post.php	(revision 18064)
+++ wp-includes/post.php	(working copy)
@@ -55,6 +55,7 @@
 		'rewrite' => false,
 		'query_var' => false,
 		'show_in_nav_menus' => false,
+		'supports' => array( 'comments' ),
 	) );
 
 	register_post_type( 'revision', array(
Index: wp-content/themes/twentyeleven/comments.php
===================================================================
--- wp-content/themes/twentyeleven/comments.php	(revision 18064)
+++ wp-content/themes/twentyeleven/comments.php	(working copy)
@@ -12,6 +12,14 @@
  * @since Twenty Eleven 1.0
  */
 ?>
+
+<?php 
+/* Return early if post_type does not support comments. */ 
+if ( ! post_type_supports( get_post_type(), 'comments' ) ) { 
+	return; 
+} 
+?>
+
 	<div id="comments">
 	<?php if ( post_password_required() ) : ?>
 		<p class="nopassword"><?php _e( 'This post is password protected. Enter the password to view any comments.', 'twentyeleven' ); ?></p>