I have configured a Samba based PDC server . When i use testparm to test smb.conf file, it shows no error.

But when I try to add a win XP machine to this domain it shows unknown user or bad password for root user. And access denied for other users.
I have made sure all users exists and their samba password is also set.

My smb.conf file is as given below.

netbios name = server
workgroup = abc

wins support = yes

domain master = yes
local master = yes
preferred master = yes
os level = 255

security = user
encrypt passwords = yes
domain logons = yes

logon path = \\%L\profiles\%u\%m

logon drive = G:
logon home = \\server\%u\.win_profile\%m

time server = yes

logon script = logon.bat

# domain admin group = root nikhil

add user script = /usr/sbin/useradd -d /dev/null -g 100 -s /bin/false -M %u

host msdfs = yes
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[netlogon]
path = /usr/local/samba/lib/netlogon
writable = no
browsable = no

[profiles]
path = /home/smbntprof
writable = yes
create mask = 0600
directory mask = 0700
browsable = no

[homes]
comment = Home Directory
browsable = no
read only = no
map archive = yes

[dfs]
comment = dfs share
path = /usr/local/samba/dfs
msdfs root = yes

Please someone help me to solve this problem.

did u use this command to add root to smb passwd?

$smbpasswd -a root

if u didnt do it and try.