[Samba] creds_server_check failed. Rejecting auth request

[Beginner]

Hi,

smbd Version 3.0.23c-2 on FC6. tdbsam backend.

I am trying to migrate my domain from a window box to linux. I have 
created all the user accounts and some of the machine accounts. I 
downed the Windows box and brought the Linux box on-line with same 
workgroup name as the old PDC. The smb.conf looks good according to 
http://www.samba.org/samba/docs/man/Samba-HOWTO-
Collection/FastStart.html#id293585

I tried to login from one of the machine who's account had been 
manually added using useradd and pdbedit but the windows XP client 
reports that the "domain controller is down or otherwise unavailable, 
or the computer account does not exist.". 

The machine's (netbios) log file reads: "_net_auth2: 
creds_server_check failed. Rejecting auth request from client MACHINE 
machine account MACHINE$

While it's IP based log file reads:
write_data: write failure in writing to client 194.200.237.218. Error 
Connection reset by peer
Error writing 5 bytes to client. -1. (Connection reset by peer)

The machine (and user account) exist:
MACHINE$:1039:7FC437F1319DDAD9AAD3B435B51404EE:A7964C61D6DBBB0341E7105
A5F1B70E4:[W          ]:LCT-45E30EF2:

I can't see anything relevant that would explain the problem, and all 
the searches I have made on this error refer to a ldap backend which 
I am not using. 

Does anyone have any suggestions that I could try?
TIA,
Dp.