After I enter the game and click on it to get it in focus, I can move around with the arrow keys and space bar normally. As soon as I try to type into chat, the first character appears and nothing else happens. Then the game responds irregularly to the arrow keys, space, enter, or camera view. Movement by point and click works normally. If I hold down an arrow key, the game responds and I start moving. But releasing the key does not immediately stop motion; motion without key press continues for around 30 seconds.
I'm on a beta version of Safari (5.2) on Mac OS X 10.7.3 with Flash plugin version 11.1.102.62