VPN connections

Trying to set up a vpn connection from my home to the office. I used the New Connection Wizard in Win XP Pro (SP3)  to create the connection to the vpn on my PC. The device listed in the Network control panel for this connection is WAN Miniport PPTP

When I click the shortcut that was created and log in with user name/password, it seems to connect, showing bytes sent/received when I hover over the icon on the system tray. But when I try to map network drives, it fails saying "no network detected".

The IT people at the office say they can use my account info to log in via vpn so the account was set up correctly. 

Any thoughts / suggestions how to fix this?

Thanks!