In my experience, here's how using VNC works in the Linux world:
1. A user logs on to a given server -- via telnet, ssh, locally, whatever
2. That user launches a VNC server instance (by typing 'vncserver'). The first time this happens, you
are prompted for a session password.
3. The server instance starts, and the user is told what X Display it's running on. For example:
New 'host.localdomain.com:1 (username)' desktop is localhost.localdomain.com:1
where the :1 indicates that X display 1 is used by this instance of VNC.
4. Anyone can now connect to that VNC instance by either:
Typing 'host.localdomain.com:1' as the target in the VNC Server window, or
Pointing a web browser to 'host.localdomain.com:5901'
(would be :5902 if the X display was 2, :5903 if the X display was 3, etc.)
Is this not how you are trying to access the VNC server? I'm not sure I understand how you're trying to connect. The more I look at it, the more it looks like you're making some sort of gateway connection, and then being offered a choice of several different servers to connect to (with the option to specify one not on the list)...