Index: pathauto.module
===================================================================
--- pathauto.module	(revision 1893)
+++ pathauto.module	(working copy)
@@ -283,7 +283,7 @@
     // If there is a pattern, show the automatic alias checkbox.
     if ($pattern) {
       if (!isset($node->pathauto_perform_alias)) {
-        if (isset($node->nid)) {
+        if (!empty($node->nid)) {
           // If this is not a new node, compare it's current alias to the
           // alias that would be genereted by pathauto. If they are the same,
           // then keep the automatic alias enabled.