[Samba] 3.0 PDC Cannot find root user

[Burhan Khalid]

Greetings :

   I've googled for this, but only found one article, and I'm not even 
sure if that is the dealing with my problem.

   I have a linux server running 3.0.2a-r1 as a PDC.

   Following the guide found here 
http://www.oreilly.com/catalog/samba2/book/ch04.html and am having 
problems with the root user not being recognized.

   I have added the root user using smbpasswd -a root, and have verified 
that the account exists in the smbpasswd file.  I have restarted samba 
after the changes, but it still will not recognize root as a valid user 
(when trying to add a computer to the domain).

  smb.conf
  [global]

     workgroup = kuwaitnet
     netbios name = sandbox
     server string = Sandbox Linux Server
     socket options = TCP_NODELAY IPTOS_LOWDELAY SO_SNDBUF=8192 
SO_RCVBUF=8192

     os level = 65
     preferred master = yes
     local master = yes
     domain master = yes
     domain logons = yes

     security = user
     encrypt passwords = yes
     log file = /var/log/samba/log.%m
     log level = 5
     max log size = 50
     hosts allow = 127.0.0.1 192.168.0.0/255.255.255.0

     logon home = \\%L\%U\
     logon drive = H:
     logon path = \\%L\profiles\%U
     logon script = netlogon.bat

     smb passwd file = /etc/samba/private/smbpasswd

     time server = yes

     wins support = yes
     name resolve order = lmhosts hosts bcast

     domain admin group = @root

     add user script = /usr/sbin/useradd -d /dev/null -g 501 -s 
/bin/false -M %u

Can anyone give me any hints? Does this have to do with the registery hacks?