Problem solved. Here's the issue. Netscape is saving the cert. If you have reinstalled courier or the OS on the machine on which the cert was generated, the authentication will fail, but the cert doesn't match the cached one. Try removing the cert from netscape's settings (Under Communicator->Tools->Security Info). After removing that cert and re-authorizing it, all works perfectly. I found this out because we were actually having the same issue with same-named certs with the web server and SSL.

John