i am writing a perl /cgi program to implement the concept of SNMP Get request and the cgi page which takes IP address, Community, OID values ...once user clicks submit button then u have to show the result of that particular OID but when i am trying the create a session object i am getting an error snmp session cannot be created. i am new to SNMP and i think i am missing out some thing very fundamental i have tried it out in different ways and in a normal snmp program i could create the session easily and get the OIDs information so i need ur help. my code is

 #!/usr/bin/perl
## CGI /Perl Prog to get the OID and
## using get _req getting the reqested data


use strict;
use Net::SNMP;
use CGI qw(:standard);
use CGI::Carp qw(fatalsToBrowser warningsToBrowser);  ## Used to see i
+f any errors in fix it out

    my ($IP,$Cmty,$Oid);
    my $ob = new CGI;
    print $ob->header;
    print $ob->start_html(-title=>"SNMP Get_Request" );
    print "<Center>";
    print $ob->h2("<i><u>SNMP Get Requested Information</u></i>");
    print $ob->hr;


    if ( $ob->param() )
     {
      $IP = $ob->param('ip');
      chomp($IP);
      $Cmty = $ob->param('community');
      chomp($Cmty);
      $Oid = $ob->param('oid');
      chomp($Oid);
      print $ob->b("INFO");
      print $ob->em(" IP : $IP Community: $Cmty Oid : $Oid <br> ");

      my $sesobj = &createSession($ob,$IP,$Cmty);
      print $ob->em("Session Obj : $sesobj");
     }

       else
   {
      print $ob->start_form(-name=>"get_req",-method=>"POST",
                            -action=>"http://localhost/cgi-bin/cgiprog
+/snmp/get_req.cgi");
      print $ob->em("IP Address ");
      print $ob->textfield(-name=>"ip");
      print $ob->br($ob->br);
      print $ob->em("Community ");
      print $ob->textfield(-name=>"community");
      print $ob->br($ob->br);
      print $ob->em("Object ID  ");
      print "&nbsp &nbsp";
      print $ob->textfield(-name=>"oid");
      print $ob->br($ob->br);
      print " &nbsp &nbsp &nbsp &nbsp ";
      print $ob->submit(-name=>"Submit", -value=>"Submit" );
      print " &nbsp &nbsp &nbsp &nbsp ";
      print $ob->reset;
   }

    print $ob->end_form;
    print $ob->end_html;

    sub createSession()
     {
      my ($object, $ip, $cmty) = @_;
    ##  print $object->em("IP : $ip <br> Cmty : $cmty <br> " ); ## Che
+cking whether val r obtained here or not
      chomp($ip);
      chomp($cmty);
      my ($session, $error) = Net::SNMP->session(-hostname => $ip,
                                                 -community=> $cmty,
    -port => '161'
                                              );
      if (!defined ($session))
       {
         print ("Err Creation Session Obj: $session->error ");
         exit 1;
       }

      else
       {
          print "Session created ";
       }
     }
[download]

Error :Creation Of Session Object ->error

Thanks In Advance