diff --git a/notifications_anonymous/notifications_anonymous.pages.inc b/notifications_anonymous/notifications_anonymous.pages.inc
index 602e377..e053970 100644
--- a/notifications_anonymous/notifications_anonymous.pages.inc
+++ b/notifications_anonymous/notifications_anonymous.pages.inc
@@ -12,7 +12,14 @@ require_once drupal_get_path('module', 'notifications') . '/notifications.pages.
  * 
  * As it needs an address every time, no need for signed pages
  */
-function notifications_anonymous_page_subscribe($type, $fields, $values, $send_interval = NULL, $send_method = NULL) {
+function notifications_anonymous_page_subscribe($type = NULL, $fields = NULL, $values = NULL, $send_interval = NULL, $send_method = NULL) {
+  //ensure that the required parameters were passed to the page
+  if (empty($type) || empty($fields) || empty($values)) {
+    drupal_set_message(t('Subscription parameters missing'), 'error');
+    drupal_goto();
+    drupal_access_denied();
+  }
+
   $account = drupal_anonymous_user();
 
   // Build subscriptions object