samba - Oct 2005 - Samba PDC - Windows XP Logon with Service Pack 2

I am running samba 3.0.20b as a PDC on Fedora core 4 with LDAP 
authentication. Everything works fine for Windows XP client workstations 
that are not running SP2.

However, SP2 clients fail with a blue screen when logging on with a 
message stating that the Windows Logon process terminated. If I remove 
SP2, the problem goes away.

Thanks in advance for any hints or tips.

Fred