diff --git a/guestbook.module b/guestbook.module
index 8e3db8a..bade800 100644
--- a/guestbook.module
+++ b/guestbook.module
@@ -623,8 +623,8 @@ function guestbook_form_entry_form_submit($form, &$form_state) {
     // Anonymous user.
     $fields = array(
       'anonname' => $form_state['values']['anonname'],
-      'anonemail' => $form_state['values']['anonemail'],
-      'anonwebsite' => $form_state['values']['anonwebsite'],
+      'anonemail' => isset($form_state['values']['anonemail']) ? $form_state['values']['anonemail'] : '',
+      'anonwebsite' => isset($form_state['values']['anonwebsite']) ? $form_state['values']['anonwebsite'] : '',
       'author' => 0,
       'recipient' => $uid,
       'message' => $message,
@@ -667,8 +667,8 @@ function guestbook_form_entry_form_edit_submit($form, &$form_state) {
       db_update('guestbook')
         ->fields(array(
           'anonname' => $form_state['values']['anonname'],
-          'anonemail' => $form_state['values']['anonemail'],
-          'anonwebsite' => $form_state['values']['anonwebsite'],
+          'anonemail' => isset($form_state['values']['anonemail']) ? $form_state['values']['anonemail'] : '',
+          'anonwebsite' => isset($form_state['values']['anonwebsite']) ? $form_state['values']['anonwebsite'] : '',
           'message' => $form_state['values']['message']['value'],
           'message_format' => $form_state['values']['message']['format'],
         ))