Not trying to outdo you danklinck. Honest!! but I had a quick look on limewire for pimsleur mandarin and the problem I noticed was that the mandarin course is not seeded very well, that is, there are not many people offering it, so it would take a very long time to download. Plus the course which consists of many lessons is scattered over many files and I'm not even sure if the whole course is available.
So I would stick with the Bit Torrent download. If the torrent file opens ok, it would be far more stable and faster, plus you got the entire course on one file.