Thanks for reporting this, and sorry for the problem. This may be an error that we already fixed, and is only affecting older versions of the game. Can you please check to see if there is an update for your version of the game? Here's how:
Go to the Windows 8 start screen by pressing the windows key on your keyboard, or pressing the windows button on your tablet.
Tap the green Store tile. If you can't find it, you can type the word "Store" on your keyboard to bring it up.
In the Store, tap the green text in the upper-right corner that says "Updates". This appears whenever any of your apps have updates available. If you don't see it there, all of your apps (including this one) are already up-to-date.
On the App updates screen, tap "install" at the bottom to install all of your available updates. If the game appears in the list, then there is an update for the game available, and you'll need to tap this game's update listing to get it.
We also have an update planned for mid-March to address some new issues, so keep an eye out for that update too. Thanks for playing!