Ok, now the problem is actually a real one. Unfortunately, my web-host is terrible, and sometimes it happens that the download stops at a certain point, before the entire file is downloaded. Obviously, the resulting file is corrupt.
I've never been able to understand when that happens, and if it also has to do with the browser used.
The only thing I can suggest is to try a lot of times, until the filesize matches the one reported on the site (or until the archive isn't corrupt).
And, if you want, I can send the game to you by email.
EDIT: Sorry, I don't know what I've drunk to do such a mistake, but I meant to post this answer in another thread, like someone cleverly noticed.