When hitting "done" at bottom right Nero 6 freezes

This happened to me once on data dvd mode and once on dvd video mode. After it was finished burning. I hit ok in the middle of the screen, then done. The program freezed for a while. Then the dvd popped out. I put it back in and windows would freeze. I tried re-burning the same movie that froze the first time and it came out fine the second time.

I’m using nero 6. Anyone know what could be causing this?