Index: wp-includes/comment-template.php
===================================================================
--- wp-includes/comment-template.php	(revision 13695)
+++ wp-includes/comment-template.php	(working copy)
@@ -1437,6 +1437,11 @@
 		$walker = new Walker_Comment;
 
 	$walker->paged_walk($_comments, $max_depth, $page, $per_page, $r);
+	
+	// Requested a non-existent page? Output the last one.
+	if ($r['page'] > $walker->max_pages)
+		$walker->paged_walk($_comments, $max_depth, $walker->max_pages, $per_page, $r);
+
 	$wp_query->max_num_comment_pages = $walker->max_pages;
 
 	$in_comment_loop = false;