Embedded PERL not working

[Miguel A. T. S. <sk8...@ho...>]

Hello all,
I'm been trying for days to extend an OID with embedded perl scripts with no results. I have followed all the instruccions I have found and really I don't understand why it is not working properly, so when I ask for an OID with snmpget or snmpwalk I allways obtain this:

root@ubuntu:/usr/share/snmp# snmpwalk -v2c -c public localhost .1.3.6.1.4.1.8072.999iso.3.6.1.4.1.8072.999 = No more variables left in this MIB View (It is past the end of the MIB tree)
root@ubuntu:/usr/share/snmp# snmpget -v2c -c public localhost .1.3.6.1.4.1.8072.999.1.2.1iso.3.6.1.4.1.8072.999.1.2.1 = No Such Object available on this agent at this OID
  I would apprecite very much if someone could take a look to this configuration and tell me what is wrong or missing.  This is the environment and configuration:

O.S.:     Ubutu 12.04.4 TLS (precise)kernel:   3.11.0-15-genericsnmpd:  5.4.3~dfsg-2.4ubuntu1.1
I'm using this example (perl_module.pl)  http://net-snmp.sourceforge.net/tutorial/tutorial-5/toolkit/perl/perl_module.pl
Add the directive into snmpd.conf
          perl do "/usr/share/snmp/perl_module.pl"

Set 0 to dont_init_agent and dont_init_lib in /usr/share/snmp/snmp_perl.pl   ( I'm not sure if this is mandatory)
           $agent = new NetSNMP::agent('dont_init_agent' => 0,                            'dont_init_lib' => 0);
start the snmpd agent:  /etc/init.d/snmpd start
Apr  4 05:58:04 ubuntu snmpd[5245]: ignoring extra call to init_agent (2)Apr  4 05:58:04 ubuntu snmpd[5245]: Turning on AgentX master support.Apr  4 05:58:04 ubuntu snmpd[5245]: NET-SNMP version 5.4.3

Using -f to exec snmpd I get:
root@ubuntu:/usr/share/snmp# /usr/sbin/snmpd -f -Lsd -Lf /dev/null -u snmp -g snmp -I -smux -p /var/run/snmpd.pidignoring extra call to init_agent (2)starting perl_module.plperl_module.pl loaded okregistering at iso.3.6.1.4.1.8072.999Turning on AgentX master support.NET-SNMP version 5.4.3Connection from UDP: [127.0.0.1]:35961->[127.0.0.1]Connection from UDP: [127.0.0.1]:53285->[127.0.0.1]

¿Am I doing something wrong? I have been surfing into documentation and posts and I can't find what is going on.  ¿Any ideas?
Thanks in advance,Miguel