[Samba] Problem with ldap backend.

[BOURIAUD]

Hello !
I've the following problem on my samba+ldap installation :
The samba server (version 3.0.28-1.el5_2.1) is running on a machine named 
luke. The ldap server runs on a machine named anakin.
Both of them seems to be setup correctly, since I can log in on the samba 
domain, but when I try to get an entry from the ldap database using the 
pdbedit command on luke, I get the following :


smbldap_open_connection: connection opened
ldap_connect_system: succesful connection to the LDAP server
The LDAP server is succesfully connected
init_sam_from_ldap: Entry found for user: david
Unix username:        david
NT username:          david
Account Flags:        [UX         ]
User SID:             S-1-5-21-215069222-2822928016-2390355089-3032
init_group_from_ldap: Entry found for group: 666
ldapsam_getsampwsid: Unable to locate SID 
[S-1-5-21-215069222-2822928016-2390355089-666] count=0
init_group_from_ldap: Entry found for group: 666
Primary Group SID:    S-1-5-21-215069222-2822928016-2390355089-666
Full Name:            david
Home Directory:       \\LUKE27\david
HomeDir Drive:        P:
Logon Script:         logon.bat
Profile Path:         \\LUKE27\profiles\david
Domain:               DOMIA27
Account desc:
Workstations:
Munged dial:
Logon time:           0
Logoff time:          Tue, 19 Jan 2038 04:14:07 CET
Kickoff time:         Tue, 19 Jan 2038 04:14:07 CET
Password last set:    Fri, 05 Dec 2008 15:16:12 CET
Password can change:  Fri, 05 Dec 2008 15:16:12 CET
Password must change: never
Last bad password   : 0
Bad password count  : 0
Logon hours         : FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

So, there is an error with ldapsam_getsampwsid, and I don't understant what it 
means. I've searched the web, found many messages, but even if I follow the 
instructions given, I can't get rid of this message.
What can be wrong in my installation ? 
Thanks for any help provided.