[Samba] Samba not accepting AD users

[Bruno Martins]

Hello everyone.

I am setting up a Debian-based file and print server and I am not being able
to authenticate with AD credentials. I think the error message is this one:
joe at sputnik:~$ tail /var/log/samba/log.__ffff_192.168.0.101
[2011/08/31 11:19:54.415130,  1] smbd/sesssetup.c:454(reply_spnego_kerberos)
  Username GALILEU-F\bmartins is invalid on this system

More information about the system:
joe at sputnik:~$ uname -r
2.6.32-5-686

joe at sputnik:~$ wbinfo -g
domain guests
domain users
domain computers
group policy creator owners
cert publishers
domain controllers
exchange domain servers
domain admins
(...)

joe at sputnik:~$ wbinfo -u
SPUTNIK\nobody
SPUTNIK\root
a230w
sqlexecutivecmdexec
ghelpdesk
pbernardo
(...)

My smb.conf:
http://pastebin.com/5vMg5X82

... and my krb5.conf:
http://pastebin.com/SE9Pmt0Y

... also my nsswitch.conf:
http://pastebin.com/psL9SksW

Can anyone please help me?

Best regards,

Bruno Martins