Something is wrong after the last update. The error reports (beta feedback) we have gotten are from IE7 browsers only. Not sure if that means its an IE7 bug only.
I'm currently doing everything I can to fix the problem, I hope to have it fixed sometime today.
Let me know what you did in the game just before the problem ocurred if you got to do anything at all. I dont have much to go on right now.
We have fixed the problem, everything should work fine now.