use LWP::UserAgent;
use LWP::Simple;
use HTTP::Request::Common;
use HTTP::Cookies;
use URI;

$mainpath='d:\\';
$url='http://darknsk.com/forum/privmsg.php';
$pageref='http://darknsk.com';
$userag='hui';

$ua = LWP::UserAgent->new;
$cookiepath=$mainpath."lwpcookies.txt";
$ua->cookie_jar(HTTP::Cookies->new(file => $cookiepath, autosave => 1));  

$h1 = new HTTP::Headers
Accept => 'application/vnd.ms-excel, application/msword, image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-comet, */*',
User_Agent => $userag,
Referer => $pageref;

$req = new HTTP::Request ('POST', $url, $h1);
$req->content_type('application/x-www-form-urlencoded');
$req->content('username=DarkSilence&subject=test&addbbcode20=white&addbbcode22=10&addbbcodefontface=0&helpbox=Цвет шрифта: текст Подсказка: можно использовать color=#FF0000&message=test3&folder=inbox&mode=post&sid=5864e05f6afb7c32282202648bfd1f75&post=Отправить');
my $res = $ua->request($req);

$otvet=$mainpath.'otvet.htm';
open(OTVET,">$otvet") || die "otvet file open failed: $!";
print OTVET $res->as_string;
close OTVET;