CiviCRM cron job running twice

All,

With full understanding that I am a novice Drupal/CiviCRM person: Yesterday, I installed the CiviCRM Cron module. In the Drupal log report, I keep seeing the following:

civirm_cron 08/27/2013 - 15:42 CiviCRM Cron Successfully Run Anonymous (not verified)
cron 08/27/2013 - 15:42 Attempting to re-run cron while it is already running. Anonymous (not verified)

When I click on the warning, it points to http:///civicrm-cron/passthrough?key=

Is this a user error or a bug?

Drupal version 7.23, CiviCRM version 4.3.5

Thanks