diff --git a/user_roles.action.inc b/user_roles.action.inc
index 05ca31e..362c1fc 100644
--- a/user_roles.action.inc
+++ b/user_roles.action.inc
@@ -55,6 +55,9 @@ function views_bulk_operations_user_roles_action_submit($form, $form_state) {
 
 function views_bulk_operations_user_roles_action(&$user, $context) {
   $roles = $user->roles;
+  if (!is_array($roles)) {
+    $roles = array();
+  }
   $selected = (is_array($context['add_roles']) ? $context['add_roles'] : array()) +
               (is_array($context['remove_roles']) ? $context['remove_roles'] : array());
   $result = db_query("SELECT rid, name FROM {role} WHERE rid IN (%s)", implode(',', array_keys($selected)));