I just joined SWC, received my login information this afternoon, logged in, and changed my password. I received the password change confirmation email, and attempted to log in with my new password. I followed all the steps in your sticky, including trying different browsers, but had no luck.
Well, I had the same problem, I login using guest still trying to figure it out. It might be the server can't save your password. A temporary solution is using a web proxy, you can then login, don't use it forever though, it just gets annoying afterwards.
Here is a good proxy for you. www.browsertunnel.com hope your problem is fixed.