[ILUG] Why NT can't explore samba?

[dan at public1.wx.js.cn]

It works with a windows95 client. but when I click the icon of the linux 
box in network neighborhood from a NT server, it pops up a windows 
that says wrong password or unknown username.  I tried put in the 
username and password as specified in the smb.conf file it tells me the 
username is not allowed on the linux machine. but the username does 
work for all windows95 clients. Could anyone tell me what's wrong 
with this NT client?
here is my smb.conf file:

# Samba config file created using SWAT
# from 192.100.200.101 (192.100.200.101)
# Date: 2000/06/07 11:36:35

# Global parameters
	workgroup = IS
	interfaces = 192.100.200.103/24

[root]
	comment = admin's share
	path = /
	valid users = root daniel supervisor
	read only = No
	create mask = 0765

[webpage]
	comment = share for admin
	path = /home/httpd/html
	valid users = root daniel supervisor gentian christine
	read only = No
	create mask = 0765

[ac]
	comment = share for accounting
	path = /home/httpd/html/ac
	valid users = root daniel supervisor gentian christine
	read only = No
	create mask = 0765

[public]
	comment = public stuff
	path = /
	guest ok = Yes