Index: user.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/user.module,v
retrieving revision 1.612.2.11
diff -u -p -r1.612.2.11 user.module
--- user.module	23 Jun 2006 07:29:18 -0000	1.612.2.11
+++ user.module	5 Jul 2006 10:44:36 -0000
@@ -345,7 +345,7 @@ function user_access($string, $account =
 
   // To reduce the number of SQL queries, we cache the user's permissions
   // in a static variable.
-  if (!isset($perm[$account->uid])) {
+  if (!isset($perm[$account->uid]) && is_array($account->roles)) {
     $result = db_query("SELECT DISTINCT(p.perm) FROM {role} r INNER JOIN {permission} p ON p.rid = r.rid WHERE r.rid IN (%s)", implode(',', array_keys($account->roles)));
 
     $perm[$account->uid] = '';