VPN Server problem

Hello,

I have a problem to establish a VPN Server on my computer. My computer is
directly connected to the internet with a valid IP address (starts with
83.x.x.x) and through a cable modem. I would like to establish a secure
connection to my father's computer (500 miles away from me) but I can not do
this. He use a cable modem and has a IP address(also starts with 83.x.x.x). I
use Remote desktop to do the configurations on his computer and that works
fine. We both have XP pro and SP 2 installed. I want to use the VPN SW in XP
pro.

He is the only user on his computer, he has a user account and a password.
On my computer we are two people who have user accounts and passwords. We
both are administrators.

When I create a VPN Server on my father's computer using the setup wizard in
XP Pro and then I create a VPN connection (using the setup wizard in XP Pro)
from my computer it works fine.

The questions are: Do two user accounts effect the possibility to create a
VPN Server? How can I solve this problem?

In the properties of the VPN server, when I create a VPN Server on my
computer with two users, her name is in the tab of user plus my user accont
and my father's user account and some more (geust, administator, remote ... ,
sql account, etc

Should I remove her account? She does not need to connect through a VPN
connection because she is already using the computer on site.

Regards,

David