Forum says to post a bug report if the MD5 Hash is wrong. I believe this is the case.
Error is ! Files mismatch
Error in POL_Download_Resource
MD5 sum mismatch ! (8 attempt)
I got the same error installing Skyrim and Age of Empires II HD so I assume its the steam install itself and not the game?
I tried filing a bug report and trying to find skyrim was impossible. When I went to submit a new one it sent me to the games page so I attempted to put the message there and didnt realize it was posting on the game page. Sorry.