There are many things that have to be right before you can connect. Here is a link so you can start learning how to configure samba, and your win98 systems.
Look first through ch3, there is information on w98 config. Check that out first.
You also need to configure /etc/samab/smb.conf. Have you done this? If not, that is necessary. You also need to add smbusers to the samba system. Have you done that?