The bottom line is that your computer needs to know where to go to resolve DNS names.
You can set this in several ways:
1) Configure your computer to use a static DNS server all the time. This should work regardless of where you are (unless the network admin is a real BOFH)
2) Configure your DHCP server to hand out the proper DNS server as part of the network configuration. For almost everyone, this just means configuring your router with the proper DNS server. Then, every computer on your home network should use this DNS server.