call to undefined function when comment.module not installed

when comments.module is not installed a call to undefined function appears.

patch included below:

Index: contributions/modules/taxonomy_dhtml/taxonomy_dhtml.module
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/taxonomy_dhtml/taxonomy_dhtml.module,v
retrieving revision 1.25
diff -u -r1.25 taxonomy_dhtml.module
--- contributions/modules/taxonomy_dhtml/taxonomy_dhtml.module	26 Aug 2003 17:13:20 -0000	1.25
+++ contributions/modules/taxonomy_dhtml/taxonomy_dhtml.module	2 Oct 2003 09:32:05 -0000
@@ -157,7 +157,10 @@
         // skip nodes not of specified type (if type was supplied)
       }
       else {
-        $detail = t("Author: %name, comments: %num", array ("%name" => strip_tags(format_name($node)), "%num" => comment_num_all($node->nid)));
+        if(module_exist("comment")) {
+          $comment_num = comment_num_all($node->nid);
+        }
+        $detail = t("Author: %name, comments: %num", array ("%name" => strip_tags(format_name($node)), "%num" => $comment_num));
         $link = l($node->title, "node/view/$node->nid", array ("title" => $detail, "class" => "dhtml_node")); 
         $term_node = array2object(array ("nid" => $node->nid, "depth" => $term->depth+1, "link" => $link));
         $part1 = array_slice($tree_node, 0, $i+1);