Usually the password is the name of the file or tracker. Go back to the piratebay and fine the .torrent and read what it say on the page about the .torrent.
You’ve just encountered a slightly refined form of torrent spam. TPB comments will usually help you avoid these because others will comment that this is a passworded archive and shouldn’t be downloaded.
Many other forums ban this, and will delete both the upload and the uploader for doing so.
One way to find the password would be (assuming pirate bay didn’t list it in the torrent post or comments) would be to visit the trackers web site, or do a search for the file name and/or torrent name in google.
Concerning not being able to view the page you were referred to, most require you to register, as you did at this forum.