VPN not working correctly.

My server windows 2003 SP1 with ISA, PPPOE to connect to the internet.

I created a vpn connection and i am connected when i ipconfig /all i get the vpn connection IP address, my server’s external IP address and my inside lan IP address, but when i try to ping by name of the inside vpn connection i get my server’s external IP address and not the private address, could it be a DNS problem?, config?
When i use my laptop and connect using a dialup and created a vpn connection i am able to connect, ping and access the inside vpn connection, i can access the resources for that vpn lan side.