samba - Jan 2007 - winbind and domain member authentication problems

Hi,
I'm having this authentication problem from a samba domain member; let's
call this machine MEMBER. From MEMBER, if I do:
  wbinfo -a usr%pwd
I receive:
  error code was NT_STATUS_NO_SUCH_USER (0xc0000064)
  error messsage was: No such user
  Could not authenticate user smediavilla%musica with plaintext password
  challenge/response password authentication failed
  error code was NT_STATUS_NO_LOGON_SERVERS (0xc000005e)
  error messsage was: No logon servers
  Could not authenticate user smediavilla with challenge/response
But I'm able to do wbinfo -u, wbinfo -g, getent passwd, and getent group

Apart from that, if I do from the PDC
  smbclient -d 3 -W mydomain -U domainuser //MEMBER/shared_resource
I get:
  Doing spnego session setup (blob length=58)
  got OID=1 3 6 1 4 1 311 2 2 10
  got principal=NONE
  Got challenge flags:
  Got NTLMSSP neg_flags=0x60890235
  NTLMSSP: Set final flags:
  Got NTLMSSP neg_flags=0x60080215
  NTLMSSP Sign/Seal - Initialising with flags:
  Got NTLMSSP neg_flags=0x60080215
  SPNEGO login failed: No logon servers
  session setup failed: NT_STATUS_NO_LOGON_SERVERS

Both of them seem related problems. My samba versions are:
* In PDC: 3.0.23c-4
* In MEMBER: 3.0.22-1ubuntu4

Even though I've seen similar problems in this and in other lists, I cannot
find a good answer.

     Thanks a lot in advance