If I understand you right, you have downloaded movies which stop after 40 sec. but they should play longer? If you downloaded the "whole" movie, it happens that the source where you download from has only downloaded a part of the original movie, so it seems that you have the whole movie but in reality you have only a part of it. Windows Media player for example shows the time scale from the original movie, so it seems that the movie stops without a reason.

Morgwen