Media center hangs when burning DVD

I am using Vista Ultimate & every time I try to burn a DVD from a program I
have recorded in media center it just gets slower & slower until media center
hangs, I can however burn jewels of the caribbean (sample included with
Vista), I have checked the resource monitor & CPU usage drops to nearly zero
when trying to burn my program, but is between 50 & 100% when burning the
sample video.

I would appreciate any help

Thank you