name resolution problem with NT Networki

I can ping server using 192.68.0.1 but when
I try to ping by “NTSERVER”, I get unknown host error in return. I tried without any DNS server installed then with. What am I doing wrong? Please help ASAP. I have a program that requires this process. I have no problems in networking neighborhood. I can see and access the server and other machines on the network. I am running NT Server 4.0 and NT Workstations and some 98 machines.