DEFCAD files are being removed from public access at the request of the US Department of Defense Trade Controls.
I got that message on the Liberator Pistol but the rest seemed to work. Although its a little hard to tell since there are soo many download buttons that just download junk.
I found another link to a cnc site which has designs you can download.
http://www.cncguns.com/downloads.html
Since the file has been downloaded it is already available via torrent (I just checked).
There is no shutting it down now.