OK, the page you followed has a lot of problems:
It shows this in /etc/hosts:
127.0.0.1 localhost
127.0.1.1 udsk-zb.zorrasbinarias.fem udsk-zb
10.5.2.212 dc2012-zb.zorrasbinarias.fem ZORRASBINARIAS dc2012-zb
10.5.2.212 zorrasbinarias.fem ZORRASBINARIAS
AD relies on DNS, so you do not need the DC lines in /etc/hosts, also you never put a netbios (ZORRASBINARIAS) name in /etc/hosts. I would replace the '127.0.1.1' with the computers actual IP.
All you need in /etc/krb5.conf is this:
[libdefaults]
default_realm = ZORRASBINARIAS.FEM
dns_lookup_realm = false
dns_lookup_kdc = true
The sample smb.conf is wrong, see here:
https://wiki.samba.org/index.php/Set..._Domain_Member
and here:
https://wiki.samba.org/index.php/Idmap_config_rid
I do not understand why the PAM files are backed up, it does nothing, also you do not have to run pam-auth-update.
He advises restarting the Samba daemons before carrying out the join, this is just wrong, you stop them before the join.
Then before the join, he gets you to kinit as Administrator, but the join doesn't use kerberos, you will just get asked for the Administrator password again.
Finally he advises making Administrator a sudo user, DO NOT DO THIS!
Add a line to smb.conf: username map = /etc/samba/user.map
And create /etc/samba/user.map containing this: !root = ZORRASBINARIAS\Administrator