Index: modules/node/node.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/node/node.module,v
retrieving revision 1.947.2.24
diff -u -p -r1.947.2.24 node.module
--- modules/node/node.module	2 Jun 2010 12:11:07 -0000	1.947.2.24
+++ modules/node/node.module	3 Sep 2010 18:44:12 -0000
@@ -931,8 +931,12 @@ function node_save(&$node) {
   node_invoke($node, $op);
   node_invoke_nodeapi($node, $op);
 
-  // Update the node access table for this node.
-  node_access_acquire_grants($node);
+  // If there is a nid, update the node access table for this node.
+  // The reasons a nid is missing are many and hard to track, but we know for sure
+  // we don't want to acquire grants if its empty because then node_access gets broken.
+  if ($node->nid) {
+    node_access_acquire_grants($node);
+  }
 
   // Clear the page and block caches.
   cache_clear_all();