samba users authentication problem

[Roger Searle]

Hi, I have set up some users with passwords using the kubuntu user 
management tool, created a file share via webmin and added those users 
as valid users for the share. As root used "smbpasswd -a" to (do what 
ever that does) for each user using the same password.  When that user 
attempts to connect to that share from an XP box, they can not do so 
with that username, the only user that can do so is my own username 
which was created prior to the serving machine booting. 

So I'm thinking something needs to be restarted on the server, have 
restarted samba, and that's not enough.  I can see the users listed as 
"valid users" for the share in smb.conf.  What have I missed?

Cheers,
Roger