[Samba] Strange SUCCESS error : connect_to_domain_password_server: machine PDCSERVER rejected the session setup. Error was : SUCCESS - 0

Mon Oct 6 07:16:48 GMT 2003

On a regular basis I obtain this message in samba log files :

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[2003/10/06 08:37:46, 0] smbd/password.c:(1313)
  connect_to_domain_password_server: machine PDCSERVER rejected the session setup. Error was : SUCCESS - 0.
[2003/10/06 08:37:46, 0] smbd/password.c:(1585)
  domain_client_validate: Domain password server not available.
[2003/10/06 08:37:46, 1] smbd/password.c:(545)
  Couldn't find user 'global' in passdb.
[2003/10/06 08:37:46, 1] smbd/password.c:(545)
  Couldn't find user 'global' in passdb.
[2003/10/06 08:37:46, 1] smbd/reply.c:(989)
  Rejecting user 'global': authentication failed
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What a "SUCCESS" error can be ? 
Does this problem came from the PDCSERVER only ?

smbd version 2.2.4 on Sun OS 5.8 (Sparc)