[Samba] user can't logon to specific computer: creds_server_check failed

[Chris St. Pierre]

A few computers -- two or three -- are very spotty about letting
people log on.  It seems -- and this could be off-base -- that they'll
let anyone log on once, but will require a reboot before you can log
on again.  Sometimes, logging on works fine, though.  There really
appears to be little rhyme or reason to what happens.

In the Samba logs, I'm getting:

[2006/10/20 08:08:14, 0] lib/util_sock.c:get_peer_addr(1225)
  getpeername failed. Error was Transport endpoint is not connected
[2006/10/20 08:08:14, 0] lib/util_sock.c:write_data(557)
  write_data: write failure in writing to client 10.8.1.182. Error
  Connection reset by peer
[2006/10/20 08:08:14, 0] lib/util_sock.c:send_smb(765)
  Error writing 4 bytes to client. -1. (Connection reset by peer)
[2006/10/20 08:08:14, 0] rpc_server/srv_netlog_nt.c:_net_auth_2(424)
  _net_auth2: creds_server_check failed. Rejecting auth request from
  client LSCHROEDER-PC machine account LSCHROEDER-PC$
[2006/10/20 08:08:14, 0] rpc_server/srv_netlog_nt.c:_net_auth_2(424)
  _net_auth2: creds_server_check failed. Rejecting auth request from
  client LSCHROEDER-PC machine account LSCHROEDER-PC$

A few days ago, I shut down Samba and removed the samba/var/locks
directory, which was recommended by a post I saw somewhere in my
Googling; this fixed it for a day or two, but the problem has
resurfaced.  We've also tried removing the machine from the domain and
deleting the machine account, and then adding the machine back in, but
that also doesn't work.

I'm running v3.0.21c.  Any ideas?  Thanks!

Chris St. Pierre
Unix Systems Administrator
Nebraska Wesleyan University