samba - Jun 2012 - XP clients cannot login after 3.5 to 3.6 upgrade

Hello,

After an upgrade from 3.3 to 3.5, we ran into this bug when we tried 
using NTLM for authentication: 
https://bugzilla.samba.org/show_bug.cgi?id=7481 .

To solve this issue, I am now trying to upgrade from the (latest) CentOS 
3.5 packages, to the "Enterprise Samba" 3.6 packages from 
enterprisesamba.org. After upgrading, the SID changed, so I changed it 
back to the old value. Next to this, I found some charset issues in the 
logs, when searching for this on the internet, I found some forum post 
about changing the unix charset to UTF-8, and this indeed helped.
The XP client I am testing doesn't want to login to the domain, the 
error I get says something that roughly translates to 'password
incorrect'.

I wrote the following script ( I use a script so I can easily retry it 
with snapshots of the CentOS/Windows VMs ), for testing, so this is what 
produces the problem:

-------
service smb stop
rpm --nodeps -e samba3x samba3x-client samba3x-common samba3x-winbind
rpm -i libwbclient0-3.6.5-44.el5.i386.rpm samba3-3.6.5-44.el5.i386.rpm 
samba3-client-3.6.5-44.el5.i386.rpm samba3-utils-3.6.5-44.el5.i386.rpm 
samba3-doc-3.6.5-44.el5.i386.rpm samba3-winbind-3.6.5-44.el5.i386.rpm
mv -f /etc/samba/smb.conf.rpmsave /etc/samba/smb.conf
sed -i 's/unix charset=.*/unix charset=UTF-8/ig' /etc/samba/smb.conf
service smb stop
net setlocalsid MYOLDSID
service ntpd stop
ntpdate pool.ntp.org
service ntpd start
service smb start
service httpd restart
-------

The only error lines I see in the logs are:
[2012/06/18 15:47:53.099572,  0] 
rpc_server/srv_pipe.c:500(pipe_schannel_auth_bind)
   pipe_schannel_auth_bind: Attempt to bind using schannel without 
successful serverauth2
[2012/06/18 15:47:53.206830,  0] auth/user_util.c:357(map_username)
   can't open username map /etc/samba/smbusers. Error Permission denied

I already did a chmod 777 (for test) of the smbusers file, didn't help. 
The other line shouldn't do harm, according to earlier mailings to this 
mailing list.

Best regards,
Gerben van Ek