Windows 2K VPN Through Pix 515

I have a Win2k Machine set up as a VPN Server, and a Cisco PIX 515 Firewall (Ver 6.1). There is an outside location with one Win2K Pro machine connected to the internet by DSL. I have configured the PIX to open ports 1723 and 47. However I can not get a connection. It will get as far as “Verifying User Name and Password” Then it will give me Error 721 “Remote computer not responding”
I believe that the Firewall is to blame but am not sure. I used Conduit commands to open 1723 and 47. Is this correct? Any suggestions would be greatly appriciated.