Please try again in 30 minutes or so. I have sent a purge request to our file hosting provider, so any corrupt copies, which may have been cached somewhere, should be wiped soon. As a result, your download speed may be reduced at first, but I'll see if I can send a request to propagate the files across the mirror network.
You may have to remove the game from the Downloader and add it back again.
If this isn't fixed within 30 minutes, please send me a PM.