Windows 2000 client cannot resolve DNS

[killasooty]

I have an SBS 4.5 Server (windows NT 4, SP6a) acting as the internet gateway for a small office network. I also have two workstations with WS_FTP installed -

One is a Windows 98SE system - this pc can publish files to our external web server using WS_FTP or Dreamweavers own publish function

The other PC is running Windows 2000 Workstation - I have installed the same software with the same proxy settings - but I cannot connect to the outside world using ftp from this system - WS_FTP & Dreamweaver both fail - unable to resolve the DNS name

http://www.mumble.co.uk

to an address.

It seems that Windows 98 is able to do this even though the server has no DNS Server process running - how should I set up the server to provide the data required for the W2000 system?

thanks in advance