I am really pissed about the fact, that Lighthouse tutorial web (http://www.lighthouse3d.com/) is throwing me 403error forbidden. Don't you know what they are doing, or will it be in the future online? I helluva need it to my school.
As Rudolf said, the website is experiencing problems on server side.
But, if you want to check something urgently here is a useful link:
http://web.archive.org/web/20130216083928/http://www.lighthouse3d.com/