Well, I am not 100% sure. There's been quite a lot of maitnence on the game itself lately. Maybe that has something to do with it, like when you tried to download, they were doin something.
I do know it is compatable. Keep trying to download it.
If you're still having that issue. Try downloading steam, and download Toribash for free on it. Usually when the standalone version is giving me trouble, steam version comes to the rescue.