Minecraft 1.6.0.1 Bugs and glitches

Hi, it's one of the testers for the Minecraft Beta update. I reviewed the app, the only things so far functional is the Add Friend button, Worlds, Friends and Servers tabs, and that's it. When I load a server my game crashes, and when I load my worlds it hangs on the loading screen and never loads. Btw the version being tested is 1.6.0.1 if you need some more detail. Maybe a hotfix or two will do the magic. Mojang, please help.