diff --git a/modules/callbacks.inc b/modules/callbacks.inc
index e7c283a..8a9ab9b 100644
--- a/modules/callbacks.inc
+++ b/modules/callbacks.inc
@@ -690,7 +690,7 @@ function entity_metadata_no_hook_node_access($op, $node = NULL, $account = NULL)
 /**
  * Access callback for the user entity.
  */
-function entity_metadata_user_access($op, $entity = NULL, $account = NULL, $entity_type) {
+function entity_metadata_user_access($op, $entity = NULL, $account = NULL, $entity_type = NULL) {
   $account = isset($account) ? $account : $GLOBALS['user'];
   // Grant access to the users own user account and to the anonymous one.
   if (isset($entity) && $op != 'delete' && (($entity->uid == $account->uid && $entity->uid) || (!$entity->uid && $op == 'view'))) {
@@ -781,7 +781,7 @@ function entity_metadata_comment_properties_access($op, $property, $entity = NUL
 /**
  * Access callback for the taxonomy entities.
  */
-function entity_metadata_taxonomy_access($op, $entity = NULL, $account = NULL, $entity_type) {
+function entity_metadata_taxonomy_access($op, $entity = NULL, $account = NULL, $entity_type = NULL) {
   if ($entity_type == 'taxonomy_vocabulary') {
     return user_access('administer taxonomy', $account);
   }