--- heartbeat.module.original   2013-05-13 12:52:28.135552000 +0200
+++ heartbeat.module    2013-05-13 12:53:29.239553590 +0200
@@ -332,8 +332,9 @@ function heartbeat_block_info() {
 function heartbeat_block_view($delta = '') {

   if ($delta == 'heartbeat_active_users') {
-    $block['subject'] = t('Most active users');;
-    $block['content'] = drupal_render(heartbeat_api_most_active_users(variable_get('heartbeat_active_users', 'default')));
+    $block['subject'] = t('Most active users');
+    $most_active_users = heartbeat_api_most_active_users(variable_get('heartbeat_active_users', 'default'));
+    $block['content'] = drupal_render($most_active_users);
     return $block;
   }