[Samba] session failed - access denied

[Beginner]

Hi,

PDC: WinNT4.
SMBD: 3.0.10

I keep hitting problems with a samba server maintaining it membership 
of a WinNT PDC. I added the server via server manager then use net 
rpc to join the domain from the samba server. All was well for a week 
but today, connections were refused with a "No logon server 
available".  

The event viewer had the error:
The session setup for from computer ... failed to authenticate. The 
name of the computer referenced in the security database was .... The
following error occurred: Access denied.

I think this is due to the password change that takes place every 
seven days but I do not understand why the passwords and not being 
changed correctly. I have disabled the firewall and turned selinux to 
permissive so i can't see any reason why the secure channel wouldn't 
work.

There is an article at MS that appears relevant but doesn't help from
a *nix box. http://support.microsoft.com/kb/150518

At the moment I am having to remove the server from the domain, add 
it again and then net rpc join the domain again. I had to do it twice 
today for some reason.

Can anyone advice me on a solution?
Thanx,
Dp