Chron jobs

Hi,
i have a problem, i made a form that have in event load a function to send mail.
this is the page :

http://creator.zoho.com/spike75/gestione-volo-libero-monte-caio20/#Form:INVIO_mail_prova

when i call url from firefox, mail sended. But if i put link in a web chron, script don't send email....

why?

THanks for all