One XP home client always stops printing to a network printer having a printer spool on a unix server.
In such cases we have to reinstall the printer driver and reboot, and it starts to to print again for some days.
Strange, but specifying the unix password of the user seemed the help, too.
However, I do not think it was a password issue; if it were, how could I temporarily solve it previously by re-installing the printer driver on the client?

An other issue: Some of our XP home clients insist on trying to connect (and get denied) to samba services as the default XP administrator user, though that user account was renamed to the actual username (the latter being identical to the samba and unix username) immediately after installation, and all shares are mapped on the actual username.
I never experienced this behaviour on machines where a limited user account was created beside the default administrator account on the XP.
Does anyone know the reason for this problem?

I have had a similar problem that is fixed by restarting samba, I don't yet have a solution but restarting samba may be easier than re-installing the drivers.

I am not quite sure what you are asking, how is samba setup? is it the PDC? or is it security=share?

I have a samba PDC here and for the XP users they have a usrename on samba and then I log in to the XP machine as administrator and add their samba username in users and passwords (is that what it's called? or is that under 2k?). With the samba user added I add tat user to the administrator group and then they have full function over there local pc sa well as all the network resources.

if this is not what you meant please let me know