samba - Sep 2010 - Spoke too soon - problems with logons using new PDC

Hi -

Linux: Ubuntu 9.10 all updates applied as of 9/5/2010.
Samba: 3.4.0

smb.conf global section:

[global]
netbios name=blahblahblah
sever string=Domain Master
workgroup=blahblahblah
encrypt passwords=true
wins support=yes
domain master=yes
local master=yes
preferred master=yes
os level=255
security=user
domain logons=yes
passdb backend=smbpasswd
logon script=%U.bat
add machine script=sudo /usr/sbin/useradd -N -g machines-c Machine -d 
/var/lib/samba -s /bin/false %u


I've been working on migrating an older PDC to a new machine.  Logging 
on is problematic.  Right now, I've constructed a miniature LAN in my 
office using an 8-port switch connecting the PDC to either a laptop or 
my desktop machine (both running XP w/SP 3).

I am able to log on to all accounts from the laptop when it is connected 
to the PDC.  No problems.

I am only able to log on to my own account from my desktop.  When I try 
to log on to any other account I get the message, "The system could not 
log you on.  Make sure your User name and domain are correct, then type 
your password again.  Letters in passwords must be typed using the 
correct case."

The only thing I can think of is that the machine account for the laptop 
was created on the new PDC, while the machine account for my desktop was 
migrated over from the old one.  I would guess that this may have 
something to do with the issue, but it seems strange to me that I CAN 
log on to the new PDC using my account if that's the case.

As always - any assistance would be greatly appreciated.

Greg