#all this works:
my $xmlsimple = XML::Simple->new();
my $response = $xmlsiple->XMLin($xml_content->content);
print "resultid:" . $response->{channel}->{result}->{resultid};

#this doesn't work:
my $resultid = $response->{channel}->{result}->{resultid};
print "resultid: " . $resultid;

##</code><code>##

  use XML::Simple;
  use LWP::Simple;
  use Data::Dumper;
  use HTTP::Request::Common;
  use LWP::UserAgent;

  my $url = "http://localhost/xml/add_order.xml";

  my $UserAgent = LWP::UserAgent->new(agent => 'perl post');

  my $xml_content = $UserAgent->request(POST $url,["userid" => $userid, 
                                                   "password" => $password,
                                                   "projectid" => $projectid,
                                                   "ordertypeid" => $ordertypeid,
                                                   "orderdateid" => $orderdateid,
                                                   "accountid" => $accountid,
                                                   "segcodeid" => $segcodeid,
                                                   "marketid" => $marketid,
                                                   "marketday" => $marketday,
                                                   "marketmonth" => $marketmonth,
                                                   "marketyear" => $marketyear,
                                                   "putcall" => $putcall,
                                                   "strikeprice" => $strikeprice,
                                                   "bs" => $bs,
                                                   "quantity" => $quantity,
                                                   "orderprice" => $orderprice,
                                                   "entered_by" => $entered_by
                                                   ]);

  print $xml_content->error_as_HTML unless $xml_content->is_success;

  #if we want to see the XML
  #printf $xml_content->content;
  #            also see ->code, ->is_info, ->is_success, ->is_error, ->header, ->message, etc

  my $xmlsimple = XML::Simple->new( );
  my $response = $xmlsimple->XMLin($xml_content->content);

  #if we wanted to see the object as a structure:
  #printf Dumper($response);

  if ($response->{channel}->{error}->{errorid} == "") {
    print "resultid: " . $response->{channel}->{result}->{resultid} . "\n";
    print "resultdesc: " . $response->{channel}->{result}->{resultdesc} . "\n";
    print "orderid: " . $response->{channel}->{result}->{orderid} . "\n";

    my $resultid = $response->{channel}->{result}->{resultid};        #ERROR
    my $resultdesc = ${\$response->{channel}->{result}->{resultdesc}};    #ERROR
    my $orderid = $response->{channel}->{result}->{orderid};          #ERROR
    
    printf "ERROR resultid:" . $resultid . "\n";
    printf "ERROR: resultdesc:" . \$resultdesc . "\n";      
    printf "ERROR: orderid:" . $orderid . "\n\n";        
    
  #  foreach my $tmp (@{$response->{channel}->{result}}) {
  #    print "resultid: " . $tmp->{resultid} . "\n";
  #    print "resultdesc: " . $tmp->{resultdesc} . "\n";
  #    print "orderid: " . $tmp->{orderid} . "\n";
  #    print "\n";
  #  }
  } else {
    print "errorid: " . $response->{channel}->{error}->{errorid} . "\n";
    print "error desc: " . $response->{channel}->{error}->{errordesc} . "\n";
    print "\n";  
  };

  my @ret_arry = ("test",
                  $resultid, 
                  $resultdesc, 
                  $orderid);
                  
  printf "ret_arry0:" . $ret_arry[0] . "\n";
  printf "ret_arry1:" . $ret_arry[1] . "\n";
  printf "ERROR ret_arry2:" . $ret_arry[2] . "\n";
  printf "ERROR ret_arry3:" . $ret_arry[3] . "\n\n";  
  
  #%ret_hash = (resultid => "a",
  #             resultdesc => "b");

  return @ret_arry;

##</code><code>##

Adding order
resultid: 0
resultdesc: Success - Order 109 has been added to ProjectID 4217.
orderid: 109
ERROR resultid:0
ERROR: resultdesc:SCALAR(0x181187c)
ERROR: orderid:109

ret_arry0:test
ret_arry1:
ERROR ret_arry2:
ERROR ret_arry3:

array: test   

arry0: test
arry1: 
ERROR arry2: 
ERROR arry3: 

done