samba PDC-- trust relation fails
 

Hello, *

we have a server (Debian) running Samba version 3.6.6 serving about twenty workstations running Windows 7.
All of a sudden, all users are unable to log in, with the message "The trust relationship between this workstation and the primary domain failed."
Some googling shows that the problem is not unknown, and the usual solution seems to be to remove it from the domain, set it to a workgroup (then restarting the client), then reinstating the domain membership (then restarting the client; it remains windows, after all...), then again trying to log in. Unfortunately, the message does not go away.
I tried a few other things, e.g. removing the machine entry from the server (by deleting it from /etc/passwd and the samba database, then reinstating it), also to no avail. And of course entering a new user and trying if he would be able to log in, nope.
I have also found that at some time, the local DNS (which is maintained by the ISP) gave a wrong IP address back when I pinged the Linux server. That might explain the problem (if the login server is not found, it would be hard to establish any relation whatsoever :-) ); however, after this problem was corrected, the login problem still existed.
Now we seem to be stuck. Any suggestion is welcome...

We discovered that a recent update (Debian) probably caused teh problem. We do not have too much detail info, but we downgraded to an earlier release, and that worked more or less.