This fix took me forever to find, so I thought I'd just throw it on here for the masses.  ...Not that many of the "masses" come to my blog.

I upgraded VMware Server on two of our Redhat 4 systems here in the last week.  The first was a test run, and went flawlessly.  The actual production upgrade went fine, but then I couldn't log in to the new web-based management interface for VMware.

I could open the login page by going to "https://servername:8333".  Then I'd enter the username and password, and promptly be presented with the error "Web service not available."  After much searching, I finally found the answer for my scenario:

Apparently, my hosts file had "localhost" pointing to the actualy IP address of the server, and not "127.0.0.1".  I corrected this, and voila!  I was instantly able to log in to the management interface.

That's it.  Short and sweet.  I hope this post helps some of you out there who are upgrading to VMware Server 2.