Ipdiscover in Linux Agent doesn't work

Dear people, I have a Ocsinventory-Unix-Agent-2.4.2 agent, it works OK but it doesn't execute ipdiscover on its own network segment.

I have installed these required packages:

libmodule-install-perl dmidecode libxml-simple-perl libcompress-zlib-perl libnet-ip-perl libwww-perl libdigest-md5-perl libdata-uuid-perl ibcrypt-ssleay-perl libnet-snmp-perl libproc-pid-file-perl libproc-daemon-perl net-tools libsys-syslog-perl pciutils smartmontools read-edid nmap libnet-netmask-perl

And this is the agent log, I can't see any IP and MACADDRESS discovered at all:

[Wed Dec 26 12:10:14 2018][debug] Ocsinventory unified agent for UNIX, Linux and MacOSX 2.4.2

[Wed Dec 26 12:10:14 2018][debug] Log system initialised (File)

[Wed Dec 26 12:10:14 2018][debug] --scan-homedirs missing. Don't scan user directories

[Wed Dec 26 12:10:14 2018][debug] Accountinfo file: /var/lib/ocsinventory-agent/https:__inventario.provincianet.com.ar_ocsinventory/ocsinv.adm

[Wed Dec 26 12:10:14 2018][debug] OCS Agent initialised

[Wed Dec 26 12:10:14 2018][debug] Turns hooks on for /etc/ocsinventory/modules.conf

[Wed Dec 26 12:10:14 2018][debug] Ocsinventory unified agent for UNIX, Linux and MacOSX 2.4.2

[Wed Dec 26 12:10:14 2018][debug] Log system initialised (File)

[Wed Dec 26 12:10:14 2018][debug] Ocsinventory unified agent for UNIX, Linux and MacOSX 2.4.2

[Wed Dec 26 12:10:14 2018][debug] Log system initialised (File)

[Wed Dec 26 12:10:14 2018][debug] Calling handlers : `start_handler'

[Wed Dec 26 12:10:14 2018][debug] [snmp] Calling snmp_start_handler

[Wed Dec 26 12:10:14 2018][debug]  - Net::SNMP loaded

[Wed Dec 26 12:10:14 2018][debug] [download] Calling download_start_handler

[Wed Dec 26 12:10:14 2018][debug]  - LWP loaded

[Wed Dec 26 12:10:15 2018][debug]  - LWP::Protocol::https loaded

[Wed Dec 26 12:10:15 2018][debug] Compress::Zlib is available.

[Wed Dec 26 12:10:15 2018][debug] Calling handlers : `prolog_writer'

[Wed Dec 26 12:10:15 2018][debug] sending XML

[Wed Dec 26 12:10:15 2018][debug] sending: <?xml version="1.0" encoding="UTF-8"?>

<REQUEST>

  <DEVICEID>HOSTOCS-Agent-2018-12-14-13-32-16</DEVICEID>

  <QUERY>PROLOG</QUERY>

</REQUEST>

[Wed Dec 26 12:10:15 2018][debug] =BEGIN=SERVER RET======

[Wed Dec 26 12:10:15 2018][debug] $VAR1 = '<?xml version=\'1.0\' encoding=\'UTF-8\'?>

<REPLY>

  <RESPONSE>SEND</RESPONSE>

  <INVENTORY_ON_STARTUP>1</INVENTORY_ON_STARTUP>

  <OPTION>

    <PARAM IPDISC_LAT="100">172.31.28.0</PARAM>

    <NAME>IPDISCOVER</NAME>

  </OPTION>

  <OPTION>

    <NAME>DOWNLOAD</NAME>

    <PARAM ON="1" TIMEOUT="30" PERIOD_LENGTH="10" PERIOD_LATENCY="1" EXECUTION_TIMEOUT="120" CYCLE_LATENCY="15" TYPE="CONF" FRAG_LATENCY="5" />

  </OPTION>

  <OPTION>

    <NAME>SNMP</NAME>

    <PARAM TYPE="NETWORK" SUBNET="172.34.28.0/24" />

    <PARAM AUTHPASSWD="" TYPE="COMMUNITY" VERSION="2c" USERNAME="" NAME="zaRma23" AUTHKEY="" />

  </OPTION>

  <PROLOG_FREQ>1</PROLOG_FREQ>

</REPLY>

Please I need your help in order to discover IP's and MAC Addresses from the network that the agent belongs to.

Thanks a lot !!!