Win98 SE can't connect to printers on 2003 server

I have set up a new print server using server 2003. Most of my environment is
XP and I'm having no problems there. However, on my Win 98 SE machines, I
can see the print server when I browse the network, but if I click on the
icon, it will never connect. It will eventually tell me the computer or share
name cannot be found. I discovered quite by accident that on some of the 98
machines, if I go Start, Run, \\IP address to the server\c$, it pops up a box
asking for a password. I can just click Cancel, then I can browse the
network, select the print server, and install the printer. However, on other
98 machines, even this method won't work.

Any ideas why I'm having so much trouble connecting to the print server from
98 to install network printers from the new print server?

(I've tried going through the Control Panel, too, BTW, but it does the same
thing.)

Thanks!