First, I'm going to take a guess: "fails all mirrors" probably means you can't connect to them. Does your machine let you do outgoing FTP/HTTP connections, or is there perhaps a firewall issue? Check this by trying to connect to any known public FTP site, and by using wget or curl to access http://google.com.

If both those work but you can't install from CPAN, then we definitely do need to see the messages.