Script not working only on a computer

Hi, I remember I had similar problems in the past, but I can't recall how I solved.

Foreword: I had to install X-notifier on a new computer, and when setting up a "libero" account I discovered I forgot the account's password. Therefore I had to follow the procedure to obtain a new password, that I did with success.

Now my problem: I installed X-notifier with the script in the new computer, and everything works.

However in my OLD computer, where I did not mess with X-notifier at all, except updating the password with the new one, X-notifier says "not checked" in red beside this account name: apparently it won't check mail at all. I know it's not the script because it works on the new computer. What is even worse, if I directly click on the account name in this OLD computer, the email account gets opened correctly, so it cannot be that the password is wrong.

What might it be?

Thanks

Marco