You can get help with BitTorrent from their website. However, not being able to play a torrent you've downloaded from them isn't a problem with them, it's a problem with something else, such as your media player or codecs. You can download a codec pack such as K-Lite (google it) and this will probably fix your problem. Otherwise you can download a new media player, such as VLC player, which has many codecs preinstalled with it.
Although P2P sharing is legal, I'll try to steer clear of the grey areas here. BitTorrent is great, I use utorrent myself, but either one will suffice.
The problem doesn't appear to be your BitTorrent, but rather, the encoded video file itself. Most every full length "video" on these sites is more than likely encoded with DivX or related encoder. This happens because DivX compresses this huge "videos" down to a reasonable size (usually around 700Mbs). The problem with this is, you have to have that encoder installed on your system in order to view them. What typically happens is you get sound, but no video.
You have two choices:
1. You can download the DivX encoder and install it on your system. If it's not DivX, then you'll need to find the appropriate codec.
2. You can skip all that junk and just download VLC Media Player. It's free and I've never come across one video it won't play.
There are codec "packs" out there, that include a bunch of different codecs that you would need to see said videos. However, as stated above, with VLC player you just install and go. Good luck out there!