why “cannot find the WINS server”

In Windows 2000 server, I have installed WINS, and from the “services” console, WINS service is started. But why in “WINS” console, it just shows “cannot find the WINS server – The WINS server you specified cannot be located. The WINS server might be down, there might be network problems, or the WINS service might not be installed.”
My server has two NICs, one for internal network, the other for external network. In WINS console, I add server by the internal address 192.168.0.1, but it will automatically change to the external address.
This server has also DHCP installed.
All my clients will obtain dynamic IP through my DHCP, but the problem is: now they cannot find their neighbors in “My Network Places”.