Can anyone tell me (legitimately) why this thread has been hijacked and turned into a discussion of the legality and scope of torrent technology?
This is a *support forum*, and there are plenty of sites that discuss the legality, morality and use of torrents. Google search "torrent forum" and I think you'll be able to find something worthwhile.
As for your problem with not being able to open torrent files, I've had problems with my client not recognizing the files before. I'm not really sure this is your issue though, considering you use two different clients and neither one works.
My first suggestion would be to trash the .plists for each client, just to make sure that they're properly set-up. Then maybe try getting your torrents from a different source.
I've had my best luck with Transmission and Vuze (formerly Azureus). Both are free, good-looking and pretty stable. Vuze has more features, but Transmission is cleaner and more simple.
Also, I should ask, are you trying to open by double-clicking or cmd+clicking and using the 'open with' dialog? If you are double-clicking, check to make sure that your default app to open torrents is one of your two clients (I've had LimeWire stay as my default even after I deleted with AppCleaner...). If it's not one your clients, use 'open with' and they should appear there.