samba - Sep 2000 - Newbie problem accessing samba server

Hi all,

i just installed samba 2.0.7 and no i'm having a prblem accessing it.
First here are my config files:

smb.conf:
-------------
[global]
character set=ISO8859-1
lock directory=/usr/local/samba/var/locks/
workgroup=2GATHER
netbios name=server
domain master=yes
username map=/usr/local/samba/lib/user.map

[homes]
service type=fileservice
guest ok=yes
read only=no
----------------

user.map:
------------------
root=administrator spiegel spiegel.harald
----------------

my Linux is a SuSE 7.0
the clients are one W2K Pro and two Win98 SE Boxes.

Now i got samba up and running.

On the linux machine i can connect and transfer files to the samba server
itself and also to the windows machines.
But when I try to go the other way and connect from the Windows PCs to samba
i get an Error:
"With this account you cannot connect from this machine" (I translated
the
error message by hand from German, so it may read diffrent in the original).
I think that i have a problem with user accounts or something.

Please help me this is really urgent.

Thanks in advance

Cu Ulrich