LAN + VPN Conection – can’t hit website

Here’s the situation:

Windows 2000 Pro Box, connected to a public LAN away from the office. I tunnel in to my corporate network over TCP/IP and connect. Once I have done this, I can browse the internet and access my corporate network but I can’t hit my company’s public website while I’m connected to the VPN. If I disconnect the VPN it comes up just fine. The computer next to me is running XP and does both just fine.

Thanks for any help – the more details the better.