It's not really down to the game, I'm afraid but a flash cache issue. This game takes a lot of ram and unfortunately this causes flash to crash on regular basis.

If you can, expand your cache. Shut down any other applications like Skype you may have running in the background. Just before Cerb/Baal, clear the cache and refresh your game.

Most players find Opera the most stable of the browsers to use. After running through Chrome, FF and IE I tend to agree.

The only way this will be resolved at game level is to take a lot out. I'm sure you wouldn't want that either.