Re: session mysteriously killed

Are you perhaps storing the session data in a DB? If the field type is, say, text, and you put something large in $_SESSION, you'll have truncated data, the session manager can't unserialize it, and you will have a silent failure when they try to do their next task -- They get logged out and there it is. Add a custom error handler and you can track what is going on, by logging each function call to the handler.