Using VPN in Windows 2000

I have two PC’s connected to the internet via a Netgear Hub and a 3Com cable modem. One PC is Win95 and the other is Win2000. Using VPN, I can connect to my company’s VPN server using the Win95 PC with no problems. On the Win2000 PC, I cannot connect. I have tried almost all the various combinations of configurations, and still get the error message: error 619: port not connected.
Anyone have a clue what I am missing? Thanks.