Can someone tell me what this means?

[Bruce Ferrell]

The following is an extract from my nice Linux 2.2.0 PDC.  ZAPPA is a
workstation on my network.  I see this over and over and over.  DOmain
logins are pretty well hosed and I have no clue what to do.  HELP!!!

[2001/05/01 13:35:03, 3]
nmbd/nmbd_processlogon.c:process_logon_packet(248)
  process_logon_packet: SAMLOGON request from ZAPPA(xxx.xxx.xxx.xxx) for
ZAPPA$, returning logon svr \\ROMULUS domain MDC code 13 token=ffff
[2001/05/01 13:35:03, 1]
nmbd/nmbd_processlogon.c:process_logon_packet(70)
  process_logon_packet: Logon from xxx.xxx.xxx.xxx: code = 0x12
[2001/05/01 13:35:03, 3]
nmbd/nmbd_processlogon.c:process_logon_packet(205)
  process_logon_packet: SAMLOGON sidsize 24, len = 96
[2001/05/01 13:35:03, 3]
nmbd/nmbd_processlogon.c:process_logon_packet(212)
  process_logon_packet: len = 96 PTR_DIFF(q, buf) = 88
[2001/05/01 13:35:03, 3]
nmbd/nmbd_processlogon.c:process_logon_packet(232)
  process_logon_packet: SAMLOGON sidsize 24 ntv 1
[2001/05/01 13:35:03, 3]
nmbd/nmbd_processlogon.c:process_logon_packet(241)
  process_logon_packet: SAMLOGON user ZAPPA$
[2001/05/01 13:35:03, 3]
nmbd/nmbd_processlogon.c:process_logon_packet(248)