Can't update to ver. 1.3.1...

[Mudbill]

Did you have the 1.2 Justine update before? I'm not sure if installing that first perhaps helps, though I wouldn't think so.

Did your retail copy have a "redist" folder inside your game installation? I think I've stumbled upon some retail copies that did not use a redist folder, similar to Steam, but most retail copies do have it. Inside there is where most of the game's files are found. That might be the folder you should pick to install the update to.