Microsoft VPN – Dial-up

We have a VPN server set up and it works without a hitch. I am able to install the MS VPN connection on laptops, direct it to the proper IP address and everything works fine. One particular laptop is giving me trouble. During the VPN install process I give it the proper IP Address and it is recognized as a phone (modem) number. I have disabled the modem and it still sees it as a phone number. Any suggestions?
Thanks