ok edited, i don't know if the posted code above was sufficient, so just in addition i post the full code here

#!d:\perl\bin\perl.exe 
use warnings;
use strict;

use CGI qw(:standard);
use CGI::Carp 'fatalsToBrowser';
use LWP;
use HTTP::Request::Common;
use HTTP::Cookies;
use HTTP::Headers;
use LWP::Debug qw(+);
use URI::Escape qw(uri_escape_utf8 uri_escape uri_unescape); 
use Encode;

print "Content-type:text/html;charset=UTF-8\n\n" ;
our $page;
my $jsessionID;
my $viewState;
sub extractLinks(){
$page =~ s/\"\/search(\/.[^ ]+)+\"/https:\/\/patentscope\.wipo\.int\/s
+earch$1\" /g;
}


sub extractJSessionID(){
my $jsessionID="";

if($page =~ /(jsessionid=[A-Z0-9]*\.wapp[0-9]n[A-Z])/si){$jsessionID =
+ $1;}
return $jsessionID;
}

sub extractViewStateID(){
my $ViewState="";
if($page =~ /javax.faces.ViewState:0\" value=\"(-?[0-9:]*)/si){

$ViewState = "javax.faces.ViewState=".$1;}
$ViewState = join( "%3A", split(":", $ViewState) );
return $ViewState;

}
my $proxy = 'http://localhost:5865'; 

my $ua = new LWP::UserAgent(keep_alive => 0, ssl_opts => { verify_host
+name => 0 });    
$ua->proxy(['https', 'http', 'ftp'], $proxy);
$ENV{HTTPS_PROXY} = $proxy;    
$ENV{'PERL_LWP_SSL_CA_PATH'} = "D:\\CA_certs\\input\\certs";    
my $cookie_jar = new HTTP::Cookies();
$ua->cookie_jar($cookie_jar); 
$ua->agent('Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident
+/5.0)');

#download init page for extracting jsession id
my $response = $ua->get("https://patentscope.wipo.int/search/en/search
+.jsf");
die "Couldn't get $url", $response->status_line unless $response->is_s
+uccess;
print $response->status_line;
$page = $response -> decoded_content; 

extractLinks();
$jsessionID = extractJSessionID();
$viewState = extractViewStateID();
print $page;

my $param ='simpleSearchSearchForm=simpleSearchSearchForm&simpleSearch
+SearchForm%3Aj_idt379=ALLTXT&simpleSearchSearchForm%3AfpSearch=brushl
+ess+motor&simpleSearchSearchForm%3AcommandSimpleFPSearch=Search&simpl
+eSearchSearchForm%3Aj_idt447=workaround&$viewState';

#--------- problem part :
my $request = HTTP::Request->new('POST', 'https://patentscope.wipo.int
+/search/en/search.jsf');
$request->header('Content-Type' => 'application/x-www-form-urlencoded'
+);
$request->header('Referer' => "https://patentscope.wipo.int/search/en/
+search.jsf");
$request->header('Accept' => 'text/html,application/xhtml+xml,applicat
+ion/xml;q=0.9,*/*;q=0.8'); 
$request->header('Connection' => 'keep-alive'); 
$request->header('Cookie' => uc $jsessionID.'\; ABIW=balancer.cms41\; 
+wipo_language=en\; BSWA=balancer.bswa2'); 
$request->content($param);

$response = $ua->request($request);
$page = $response->decoded_content();

print $page;
[download]