Index: post.php
===================================================================
--- post.php	(revision 23178)
+++ post.php	(working copy)
@@ -3585,7 +3585,7 @@
 		$page = get_post( $page );
 	$uri = $page->post_name;
 
-	foreach ( $page->ancestors as $parent ) {
+	foreach ( (array) $page->ancestors as $parent ) {
 		$uri = get_post( $parent )->post_name . "/" . $uri;
 	}