It seems the URI in the ebuild no longer exists and the main web site no longer lists Linux as a supported. A resourceful person could easily find the file stuffit520.611linux-i386.tar.gz by searching but due to the legal situation with this I don't feel I can PR a fix. It will be a shame to lose this as it just saved me so the only other option would be to update the user is on their own in finding the file and is unsupported.