Can't get a Win98 PC to log onto a 2003 Domain

hello everone... I need some assistance. I am trying to get a Windows 98 PC
to log onto a 2003 domain. The client is very determined to keep this PC
because it has a lot of legacy software on it. I am able to ping the server
by name and/or address, I have installed the DSClient, and I have tried to
use DHCP or static addressing. Nothing seems to work. I tried another 98 PC
and I have the same trouble. Am I missing some security settings on the
server end?

Please help!!

Thanks
Chris