Oops. This is caused by the download provider. The file is still there, but they have it so that the link expires for individual downloaders unless I update the file manually every month, so this is only affecting those who have had Cogmind for a while. I really need to get that timer extended (or set up a reminder so I can remember to update manually...). I fixed it just now and it should work normally. Let me know if you still have any problems, and thanks for posting!
(This wasn't often an issue in the past because I tend to release every month or so, but this particular release cycle is going longer due to the Roguelike Celebration--I'm currently in San Francisco--and the fact that it's going to be the biggest release ever
)