Well the same thing has happened to me on occasion too. When I was making a FPS (first person shooter) game, it would freeze when I would test it out. And also when I was making War Zone (If you haven't seen it, you can watch it on youtube here:
http://www.youtube.com/watch?v=2WwQI7dPiAw) It would sometimes freeze before I could save it and I would lose some of my work. So I think it is just a problem with complexity. Alice cant always handle really complicated stuff like this game. So I don't think that you will be able to fix it. Think of it as a compliment to your effort whenever it freezes... unless of course you lose your work. If that happens, feel free to throw your computer out of a window.