diff --git fb.module fb.module
index 0a84fa0..5a97150 100644
--- fb.module
+++ fb.module
@@ -810,11 +810,12 @@ function fb_get_uid($fbu, $fb_app = NULL) {
  */
 function fb_get_fbu($uid, $fb_app = NULL) {
   // Accept either a user object or uid passed in.
-  if (is_object($uid) && ($uid->uid) &&
-      isset($uid->fbu) && $uid->fbu)
+  if (is_object($uid) && (isset($uid->uid)) && isset($uid->fbu) && $uid->fbu) {
     return $uid->fbu;
-  elseif (is_object($uid))
-    $uid = $uid->uid;
+  }
+  elseif (is_object($uid)) {
+    $uid = isset($uid->uid) ? $uid->uid : 0;
+  }
 
   if ($uid && !empty($GLOBALS['_fb'])) {
     // User management is handled by another module. Use our hook to ask for mapping.