You're referring to starting new threads, right? I've had no troubles responding to existing threads.
I can't think of when it would have let me go back to alter the thread's title. I haven't tried using my "back button" on my browser. I'll have to try it again and see if I can edit it.
For some strange reason, I was able to post a new thread a few moments ago, with no difficulties. I know the MSN boards have gremlins - maybe DIS does too?