>This file is downloaded using torrent software. The strange thing (and maybe it is because I don't understand how torrent program works) is that I can "open" the file within the torrent software and see all the files. But when I try to copy them somewhere I get this message that the file is too big. So it looks like the file is not corrupted.

The signature of the file and some of its header content might be ok but a great part of it seems to be in fact corrupted. That might explain why you get some out of it but not the file itself.

For that size, there is definitely something wrong. As, it would take one hell of an algorythm to compress like that. :)