samba - Jun 2005 - problems logging onto Domain from Windows98 machine

Hi

I'm having problems getting a machine to consistently successfully logon
to a SAMBA server setup as PDC on my network from a Windows98 machine.

I get the message :
'No domain server was available to validate your password.
You may not be able to gain access to some network resources.

It sometimes works ( runs the netlogon script etc ) and I've been told
I just need to wait an amount of time for the server to announce itself
but I don't believe that it what is causing the problem.

Any help gratefully received.

Mark