What does "added... to the VPN" mean? VPN is a Virtual Private Network, used to connect via a secure tunneling connection to a LAN or WAN. If your laptop is connected to your company network and they connect you to a domain and they use Group Policy to turn off Automatic Updates, using WSUS or another means to provide updates to the PC, you will not be able to use AU and OneCare will complain and tell you that you are at risk.
-steve