Video jerky when saving to video or burning to dvd

[videonewbie]

I'm using VS8SE and have tried VS9 but it does the same thing. It seems to happen on the part where the playback speed of the video is slowed down. The video views fine in the preview window with no problems but when trying to save to video or burn to disk, the part where the video is slowed down becomes jerky. Does anyone have any suggestions or maybe my settings are incorrect. My hardware should not be a problem. I have tried on 2 different machines and same thing. PLEASE HELP ME!