DVD framerate problem with Nero 7

Hello I’m a first timer so I apologize if this question has already been answered.

I currently have Vista and Nero 7 premium. Whenever I burn an avi onto a dvd with Nero, and then play the dvd the framerate seems to be choppy… not fluid for some reason. So I played the avi file using Nero’s Showtime application and noticed that the framerate was choppy on that too. However, when I play the avi file on WMP its perfectly fine and fluid.

I tried playing the dvd on a dvd player after burning with Nero but it was still choppy. Does anyone know how to solve this? Is Nero using some codecs that are not up to par with the avi file…? This happens with all my avi files also. Any help would be appreciated, thanks.