diff --git includes/bootstrap.inc includes/bootstrap.inc
index 1cf4c4d..d4484ca 100644
--- includes/bootstrap.inc
+++ includes/bootstrap.inc
@@ -1177,7 +1177,7 @@ function bootstrap_hooks() {
 function drupal_unpack($obj, $field = 'data') {
   if ($obj->$field && $data = unserialize($obj->$field)) {
     foreach ($data as $key => $value) {
-      if (!isset($obj->$key)) {
+      if ($key && !isset($obj->$key)) {
         $obj->$key = $value;
       }
     }