With the new website, some URLs have ceased to work. Dirs like docs/, repo/, files/, have been moved to the repo subdomain.
If your mirrorlist pointed to http://parabolagnulinux.org/repo, you should install the pacman-mirrorlist-libre update using pacman -U http://repo.parabolagnulinux.org/core/os/i686/pacman-mirrorlist-libre-20110305-1-any.pkg.tar.gz.
Edit: Updated the pacman-mirrorlist-libre URL.