I am having the same problem.
It ran perfectly *once*. I was extremely pleased. The second conversion I tried, it looked like it was going to do, then it just shut down. I thought maybe I had to register to get it work again, so I paid the $35US, got it registered and the same thing happened!!! I'm just trying to convert MP3s to AAC so I can play the stuff on my CD player.
I shut it down and restarted it, but it is still happening. WTH?
Did I just throw thirty bucks out the window? I notice this question has been here for a couple weeks with no replies.
Anybody at all have any clues?