I had the exact same problem and if you did too then do the following steps to fix it:

1. Open my computer.
2. Open program files
3. Open planeshift file (not setup).
4. Look for icon that is named updater.
5. Open updater
6. Sit back and watch it do its work. It will ask for you to click OK every once in a while.

After the update is complete then your set to go. I have the same name for the forum as the game. You all can thank me later!
                                        Have fun,
                                                        Chadwicked