--- path_redirect/path_redirect.module	2010-07-06 21:12:18.000000000 +0200
+++ path_redirect-NEW/path_redirect.module	2010-07-06 21:16:00.000000000 +0200
@@ -250,7 +250,7 @@
 function path_redirect_nodeapi(&$node, $op, $a3 = NULL, $a4 = NULL) {
   switch ($op) {
     case 'presave':
-      path_redirect_check_alias_changed('node/' . $node->nid, $node->path, $node->language);
+      if(isset($node->nid)) path_redirect_check_alias_changed('node/' . $node->nid, $node->path, $node->language);
       break;
     case 'delete':
       // When a node is deleted, also delete the redirects to it (they will result in a 404).