Index: taxonomy_access.module
===================================================================
--- a/taxonomy_access.module
+++ b/taxonomy_access.module
@@ -294,10 +294,15 @@ function taxonomy_access_field_info_alter(&$info)
    $old_fields = FALSE;
 
    // The entity is actually a "pseudo-entity," and the user profile form
-   // neglects to include the uid.  So, load it.
+   // neglects to include the uid. So, we need to load it manually.
    if ($entity_type == 'user') {
-     if ($account = user_load_by_name($entity->name)) {
-       $entity->uid = $account->uid;
+     // Some modules which extend the user profile form cause additional
+     // validation to happen with "pseudo-entities" that do not include the
+     // name. So, check if it exists.
+     if (isset($entity->name)) {
+       if ($account = user_load_by_name($entity->name)) {
+         $entity->uid = $account->uid;
+       }
      }
    }
    list($entity_id, , $bundle) = entity_extract_ids($entity_type, $entity);