File updater is a bit flakey.. Had exactly the same problem downloading it for the first time (work computer) a few hours ago. After seeing the posts above (yesterday), I decided to just quit the updater and start again.
After three attempts (each time it's getting further) I finally got the game to update completely.
*sadface* unfortunately my home computer has bugger all bandwidth compared to work so its a painful process the second time around.. But im hopeful that the same method will work.. eventually.