Everybody,
We've discovered a problem where attaching a firework to yourself can semi-permanently break your account. Please don't do it -- tomorrow we're going to patch the servers to fix this.
(For scripters, if you have a script that calls llDie, and it's on an object attached to an avatar, the avatar dies. Unfortunately, when you log back in the object is still attached, and tries to run again.)
Usually this appears as you being underground or flying up into the sky every time you log on.
Again, expect a fix tomorrow.
James