Hi, how did you solve it? I'm in the same situation. Everything all new from Steam, dll copied, Cherub Rock bought, dlc folder appears, CDLC copied, CDLC appears in menu, ... and the game freezes when I launch them.
Someone (maybe you) was mentioning how the game was not on his C folder. I know I had some issues with this with an Assassin's Creed game (also from Ubisoft...). Maybe the problem is the same for this game?
EDIT : woops, I actually replaced the DLC I got from another source (right one but must be another version) by the one from this page, and now it works!! Me happy