alien arena bad url

[kevinfish]

$ nix-env -i alienarena
installing alienarena-7.52' these derivations will be built: /nix/store/2jawh9145kq186wz05y06ri8n3hxjwg7-alienarena-7.52.drv /nix/store/mgzc378hxjhlc6anrck679swj2l6l4ik-alienarena-7_52-linux20110929.tar.gz.drv building path(s)/nix/store/iw56yr1jfqki8w26rj20v69wddpd8vq7-alienarena-7_52-linux20110929.tar.gz'

trying http://icculus.org/alienarena/Files/alienarena-7_52-linux20110929.tar.gz
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0
curl: (22) The requested URL returned error: 404 Not Found
error: cannot download alienarena-7_52-linux20110929.tar.gz from any mirror
builder for /nix/store/mgzc378hxjhlc6anrck679swj2l6l4ik-alienarena-7_52-linux20110929.tar.gz.drv' failed with exit code 1 cannot build derivation/nix/store/2jawh9145kq186wz05y06ri8n3hxjwg7-alienarena-7.52.drv': 1 dependencies couldn't be built
error: build of `/nix/store/2jawh9145kq186wz05y06ri8n3hxjwg7-alienarena-7.52.drv' failed