To setup a CRON Rule
Go to your hosting account and find Cron job manager, I'm using godaddy.com host and its under My account - Hosting - then Lanch your hosting,
go to tub Content, first line Cron job manager, after you in, push the button Create Cron Job,
then give a name for Cron job title: for example "Birthday Schedule" then for the Command: click Browse,
window will popup, in left column find modules, click on it, on the right window look for the file cron.php,
probably you will not find it because it in diferent directory,
so go to your FTP manager, in your root directory go to modules or watever is stored,
find birthdaypresent module, open it, find cron.php file and copy in to module folder, BUT COPY NOT TRANSFER.
Go back to your host browse again, go to module/cron.php and hit select and there you go.
You can set up time, month and days manualy.
You good to go.
Hope that helps.