I assume you do mean you tried AVIpreview to play the incomplete right? I never tried playing an incomplete mpg on any other player, so i don't know if it will do it.. I try and avoid mpgs when possible.
Perhaps you don't have an mpeg2 codec... The best would be to find someone who will give you PowerDVD or WinDVD (unforunately they are not free) - even with an mpeg2 codec some svcd's simply won't play on certain players, but PowerDVD or WinDVD will play them.
A person who asks a question is a fool for five minutes, a person who doesn't is a fool forever...