samba - Apr 2006 - samba rejection error on log level 1 with win xp pc reboots

hi all, 
 
pls forgive me if I haven't posted this correctly, this if my first
attempt

we have a samba PDC on an hpux box with 400 users logging in. all is
well. i noticed in the samba logs (log level 1) that whenever a user
reboots his pc (every day) the first time it automatically tries to map
to the samba server it gets a reject. then when the user opens up his
app it goes right in. the users arent even aware of this. if they
disconnect n remap, i dont see this error in the samba log, only when
they reboot. anyone ever seen this? 
 
thx in advance.

example:

[2006/04/19 07:01:33, 1] smbd/reply.c:(1037)
Rejecting user 'keaceve': authentication failed
[2006/04/19 07:01:40, 1] smbd/service.c:(636)
ar5046 (10.12.12.111) connect to service metashrd as user keaceve
(uid=847, gi
d=104) (pid 23430)