samba - Oct 2011 - XP Clients loose connection (offline files)

Hi,

I have an small network with about 50 Clients.
I use Samba4.0alpha14 als PDC and Samba3.5.4 als File- an Printserver on
different (virtual) machines. On both machines a bind-dnsserver is running
(master and slave).
The Samba3-Machine is configured as local master browser and as a domainmember
of the samba4-machine.

Sometimes WinXP Clients loose connection to the Samba3-Fileserver, connection
via Servername is not possible, connecting via IP works fine. So it seems to be
a problem with the dns or wins-nameserver to me.

I tried to set both Samba-machines as DNS and WINS-Nameserver or only one or the
other, nothing solved the problem.

Any opinions?

here my samba3 smb.conf:
----
[global]
        ;interfaces = br0
        ;bind interfaces only = yes   
        workgroup = MYDOMAIN
        remote announce = 192.168.73.255 192.168.178.74.255 192.168.75.255
        passdb backend = tdbsam
        admin users = "MYDOMAIN\administrator"
        printing = cups
        printcap name = cups
        printcap cache time = 750
        cups options = raw
        map to guest = Bad User
        include = /etc/samba/dhcp.conf
        logon path = \\%L\profiles\.msprofile
        logon home = \\%L\%U\.9xprofile
        logon drive = P:
        log level = 3
        usershare allow guests = No
        add machine script = /usr/sbin/useradd  -c Machine -d /var/lib/nobody -$
        #domain logons = No
        password server = theo.mydomain.net
        domain master = No
        security = ADS
        netbios name = Vera
        server string = Vera
        wins support = No
        wins server = theo
        idmap gid = 10000-20000
        idmap uid = 10000-20000
        realm = MYDOMAIN.NET   
        template homedir = /home/%D/%U 
        winbind refresh tickets = yes
        template shell = /bin/bash

-----

my samba4-smb.conf
-----
[global]
        server role = domain controller
        workgroup = MYDOMAIN
        realm = mydomain.net
        netbios name = THEO
        setup directory = /usr/local/samba/share/setup/
        server string = Theo
----

In the logs sometimes the following error shows up:
[2011/10/12 17:12:52.715255,  3] smbd/service.c:1213(make_connection)
  __ffff_192.168.178.211 (::ffff:192.168.178.211) couldn't find service
anyusername
[2011/10/12 17:12:52.715275,  3] smbd/error.c:80(error_packet_set)
  error packet at smbd/reply.c(776) cmd=117 (SMBtconX)
NT_STATUS_BAD_NETWORK_NAME

-> But that seems to be a result of the clients to syncronize offline files
of a user not logged in...


Best regards Philipp