Dial up networking

I have a laptop that I used at our work and while I am on the road. I am having problems with being able to browse our network when I dial-up. I can not see any other Systems showing in the network neighbourhood. When I am in the office and logonin the regular mood I can see the entire network and all my drives map ok.

I can access my mail and I can ping our servers via their IP address and sometimes via name when I dial up. But my drives will not map nor can I map to anything.

Any ideas?