Poormanscron 5.x-1.1 Unstable

I have used the poormanscron 4.7.x-1.0 module on production Drupal sites. I am using it for the CZEN.org website without issue. But....

In testing the poormanscron 5.x-1.1 module on Drupal 5, I have noticed some issues. It kicks off multiple cron runs simultaneously. In combination with the Notify module, this generates multiple emails sent. Poo!
Have you tested the poormanscron module on Drupal 5? Are you seeing similar?

http://drupal.org/project/poormanscron

Until this issue is resolved, I am considering poormanscron 5.x-1.1 unstable and have removed it from the pre-installed modules.

I have added a crontab as part of the configuration of the Neogene.org website.
0 * * * * wget -O - -q http://www.neogene.org/cron.php

Let me know if cron.php does not execute hourly via anonymous user.