Nero 6 Transcoding crashes

Hi ,
I’m having problems transcoding hard drive AVI files(divx, xvid) to write to dvd with nero 6 (nerovision express)

During transcoding the operation runs ok up until the video begins to play in the box (approx 45mins-1hours). The program then locks up and does not respond(no error messages). I have managed to do three files and had about 20 crashes doing them. I have downloaded the latest updates and these seemed to help as i burned nothing before them, i have also un and re-installed several times.

I’m new to this stuff (as you proberly can tell) so forgive me if the solution is obvious, i hope it is!