--- listhandler.module.orig	2008-10-29 19:34:00.000000000 +0100
+++ listhandler.module	2008-11-02 18:58:30.000000000 +0100
@@ -212,7 +212,7 @@ function listhandler_nodeapi(&$node, $op
       break;
     case 'insert': // mail new forum topics to mailing list.
       if ($node->type == 'forum') {
-        if ($node->sentbylisthandler) { // avoid running an infinite loop.
+        if (!empty($node->sentbylisthandler)) { // avoid running an infinite loop.
           // save ids in listhandler table.
           db_query("INSERT INTO {listhandler} (msgid, nid, cid, pid, uid, mid, tid) VALUES ('%s','%s','%s','%s','%s','%s','%s')", $node->message_id, $node->nid, 0, 0, $node->uid, $node->mid, $node->tid);
           // call watchdog
@@ -247,7 +247,7 @@ function listhandler_nodeapi(&$node, $op
  */
 function listhandler_comment($edit = array(), $type) {
   if ($type == "insert") { // only accept calls by the comment insert hook.
-    if ($edit["sentbylisthandler"]) { // avoid running an infinite loop.
+    if (!empty($edit["sentbylisthandler"])) { // avoid running an infinite loop.
       // save comment ids in listhandler table.
       db_query("INSERT INTO {listhandler} (msgid, nid, cid, pid, uid, mid, tid) VALUES ('%s','%s','%s','%s','%s','%s','%s')", $edit["message_id"], $edit["nid"], $edit["cid"], $edit["pid"], $edit["uid"], $edit["mid"], $edit["tid"]);
       // call watchdog