samba 2.2.2 on RH7.1 with NT server

[jtournier at idealx.com]

Hello,
i tried to configure a samba server with authentification via winbindd and a NT server.
I think my configuration is right: when i want all the user's informations by using the 
command line: "getent passwd", i can see every users.
Now, when i want to connect to the samba server from a NT client, the autentification is
not good: i have those error messages:

[2001/10/25 18:00:30, 0] smbd/password.c:domain_client_validate(1554)
  domain_client_validate: could not fetch trust account password for domain NT
[2001/10/25 18:00:30, 1] smbd/password.c:pass_check_smb(546)
  Couldn't find user 'NT+jtournier' in passdb.
[2001/10/25 18:00:30, 2] smbd/reply.c:reply_sesssetup_and_X(970)
  NT Password did not match for user 'NT+jtournier'!
[2001/10/25 18:00:30, 2] smbd/reply.c:reply_sesssetup_and_X(980)
  Defaulting to Lanman password for NT+jtournier
[2001/10/25 18:00:30, 1] smbd/password.c:pass_check_smb(546)
  Couldn't find user 'NT+jtournier' in passdb.
[2001/10/25 18:00:30, 1] smbd/reply.c:reply_sesssetup_and_X(995)
  Rejecting user 'NT+jtournier': authentication failed

What can cause my pb ? What is the "passdb" ?
Thanks
--
Jérôme