Access files on a 2003 server from a 98 client

Please let me know if I am on the right track.

I have a 2003 server and a small network (20 computers with 98-XP). When
on the XP machines, you can browse the network and see all the computers in
the workgroup. Within network neighborhood you can click on the server 2003
machine to look at files that are shared, you will get a login for username
and password. Each client has a been placed on the 2003 server and therefore
when you type in a user/pass when in XP, the server 2003 will allow you to
browse the files available. When you do the same in win 98, the login
doesn't give you a user name area just a //QB-Server (which is the server
2003) and a place to put in a password, no user name spot. Now, even if you
type in the admin password, you get a accessed denied. Does the username
have to be setup when the client logs into the windows 98 machine?

How do I set the 98 machines to force a login at the begining of the session?

Dan Abbuhl