[Samba] Windows 2008 pdc troubles

[Richard Smits]

We are in the process of upgading our windows 2003 pdc's to windows 
2008Rr2. No problem there, but our samba/winbind clients are beginning 
to show some strange behaviour.

In the beginning we saw a lot of messages appear in the logfiles.

Example :
--------------
pr  1 14:07:36 srvxxx winbindd[5148]:   rpc_api_pipe: Remote machine 
pdc.company.net pipe \NETLOGON fnum 0x4003returned critical error. Error 
was NT_STATUS_PIPE_DISCONNECTED
--------------

The clients who were connected to our 2003 pdc did not have this problem.
Now we are getting reports that some mounts are failing, and joining a 
machine to the domain is also failing with a kerberos error. (ticket not 
valid ?)

Some more messages :

----
winbindd.log :
[2010/04/01 14:54:10, 1] nsswitch/winbindd_util.c:trustdom_recv(229)
Could not receive trustdoms
----

[2010/03/31 10:02:25, 1] libsmb/clientgen.c:cli_rpc_pipe_close(386)
cli_rpc_pipe_close: cli_close failed on pipe \NETLOGON, fnum 0x4007 to 
machine pdc.company.net.  Error was SUCCESS - 0

We are using samba version samba-3.0.28-1.el5_2.1 on rhel5.

What can we do to troubleshoot or solve this problem ?

Greetings ... Richard