I'm getting the same error at about the same point in the download on two Windows 8 Pro with Media Center 64bit PCs and a Windows 8 RT device (all on same LAN). Have tried the download a half dozen times on one of the PCs, Lenovo IdeaPad Yoga 13. I've tried a number of suggested fixes including a clean boot. Nothing has worked yet.
Since it's failed to update on so many devices I'm thinking it has to be a server/connectivity issue(?)