VPN Question using Winproxy

Has anyone used Winproxy v3.0r1i and successfully configured a VPN?
I have set up a filter in Winproxy to allow incoming tcp on port 1723 and
port 47 yet it still will not let me into the network from home. I can
connect and and logon with no problem yet I can’t see or find any computers
on the network. If I close Winproxy at work, I can access everything from
home.
At the server, I am simply using PPTP on NT Server4.0 SP5.
Any help would be greatly appreciated.