VNC will not work via dial-up, help please

[Ronald Saa]

Hello all,
Heres the situation:
2 stand-alone computers in a large room,
each with access to the internet.
I want to test VNC from one to another.

Computer A logs onto the internet 
(via ISP: MCI,  dial-up 56K)
ipconfig:
67.192.238.200
255.255.255.255
67.192.238.200

Computer B logs onto the internet 
(via ISP: MCI,  dial-up 56K)
ipconfig:
67.192.238.211
255.255.255.255
67.192.238.211

Computer A runs VNC (usermode) server.(host)

Computer B (client) tries to connect by running
VNC Viewer.
I enter the host IP (67.192.238.200) but get error:
"Attempting to Connect" window...
Then "Unable to connect to host: Connection timed out (10060)"

I called MCI and they told me that their firewall
does not block any ports.

Question:
What else could it be?

Thanks in advance for any assistance.
Noni