Testing a SAMBA Domain Controller

Hello,,,

We have an existing(working) MS PDC in our office.

I have already installed SAMBA with LDAP Authentication on a TEST machine (on same LAN).

But, am unable to join a WinXP machine to this domain.

in smb.conf i have:

WORKGROUP = mydomain 

and tried to join the XP machine to mydomain

Please advise me on this.