Index: heartbeat.admin.inc
===================================================================
RCS file: /cvs/drupal-contrib/contributions/modules/heartbeat/heartbeat.admin.inc,v
retrieving revision 1.1.2.15.2.20.2.31
diff -u -p -r1.1.2.15.2.20.2.31 heartbeat.admin.inc
--- heartbeat.admin.inc	5 Jan 2010 09:12:52 -0000	1.1.2.15.2.20.2.31
+++ heartbeat.admin.inc	12 Jan 2010 22:44:35 -0000
@@ -295,7 +295,9 @@ function heartbeat_activity_stream_confi
     'num_load_max' => $form_state['values']['num_load_max'],
   );
   // populate the settings with the form state
-  $settings += $form_state['values']['settings'];
+  if (isset($form_state['values']['settings'])) {
+    $settings += $form_state['values']['settings'];
+  }
 
   $additions = array(
     'poll_messages' => $form_state['values']['poll_messages'],