NAV 5.0 Push Out To Users

Some of my machines on the network cannot get pushed to. The system keeps saying cannot resolve computer name or it cannot connect to target machine to push out the NAV product ot defs. I’m having to go locally off each machine and get the defs and in one case can’t even get the program pushed only the agent. The machines are mostly 98’s, but one is an NT. Ever run into it? I had one LAN that was pushing out to five machines and it couldn’t ever resolve the computer name thing.