--snip--
fetchmail: about to deliver with: /opt/rt4/bin/mailgate --queue general --action correspond --url http://helpdesks.ticket.co.it/ #*************************************.***************.***********sh: 1: /opt/rt4/bin/mailgate: not found
--snip--
Ok, your username is fixed and your authenticating correctly. However, its /opt/rt4/bin/rt-mailgate, not /opt/rt4/bin/mailgate. Just change that in your fetchmailrc file and you should be good to go.
-Matt
