[Ann Bens]

Usually its some sort of excotic codec like divx/xvid or Mjpeg.
Run the file through GSpot and see which codec you are missing.

[Ann Bens]

mpg is usually video and audio in one file.

[Ann Bens]

Whatever is on your timeline export with Max Render Quality (just in case) and do not use the Preview files. MPE will render new files for you. This will give a better result.

[Ann Bens]

Install the ac3 filter codec (even though Gspot says its installed)
or copy ad2ac3dec.dll from Encore CS3 root and paste in root of Premiere CS3.
https://ac3filter.net/

[Ann Bens]

You need a mjpeg codec for Nikon footage.
https://www.mainconcept.com/products/sdks/video/motion-jpeg.html

[Ann Bens]

If you installed the Microsoft Video 1 codec you might get it to work.

[Ann Bens]

How about selecting the first clip, holding Shift and selecting the 40th clip…

[Ann Bens]

Sounds like a broken CCD.

[Ann Bens]

For dvd export to mpeg2-dvd and do not make it progressive. As in CS3 you will be throwing away half you vertical resolution.
Leave it interlaced.

[Ann Bens]

Hit Update (its under Help) in the bridge, that should do the trick