[Samba] suspend/start printer problem

[Fabio]

Hi to all,
I upgrade my pdc (samba+ldap+cups) from samba 3.0.20b to 3.0.21a and
I can't suspend/restart printer from windows client. I discover (using
tcpdump) that client sends packets to server and this reply to it, so I
think the problem is in server side.
Logs (samba, cups, syslog) don't contain errors.

I would indicate this problem in bugzilla but:
- I'm not sure it's a real samba bug
- I have no error to show

How can I do a more detailed debug?

Thanks in advance,
Fabio