Well, it should have nothing at all to do with the way your computer is hooked to the internet (routers, etc) as long as it is indeed connected.
I just tried that link from my Mac (using Chimera 0.6 for OSX), and I can't download it either, which is very odd. I have absolutely no trouble downloading anything from anywhere, so this is odd. It seems, to me, to be more of a problem with the site itself. Don't assume it's a limitation of the Mac platform until the real reason for this oddity is found.