Do you use the same account information for both home and work? The game doesn't save a cookie onto your computer, like other flash games, but instead everything is saved server-side. If you're having rollback issues, it may be that either the game at work or the game at home isn't saving your game properly. Check to see if you get that "Disconnected" thing in red at the top of the screen. If you see that, click it to re-establish a connection to the game server.