this is my program:
#!/usr/bin/perl
 use strict;
 use lib '../lib';
 use Net::SNMP;

   my ($session, $error) = Net::SNMP->session(
      -hostname  => '99.1.64.65',
      -community => '12345',
      -port      => 161
   );

   if (!defined($session)) {
      printf("snmp::session ERROR: %s.\n", $error);
      exit 1;
   }

   my $sysUpTime = '1.3.6.1.2.1.1.3.0';

   my $result = $session->get_request(
       $sysUpTime
   );

   if (!defined($result)) {
      printf("ERROR: %s.\n", $session->error);
      $session->close;
      exit 1;
   }

   printf("sysUpTime for host '%s' is %s\n",
      $session->hostname, $result->{$sysUpTime}
   );

   $session->close;