You aren't trying to do a POST you are trying to do a GET, which maybe the limiting factor, though I suspect it is more likely that there is some characters in
@message that is causing the proplem. Try either:
use URI::Escape;
my $message = uri_escape(join('', @message));
Or, more sensibly, a POST request:
use HTTP::Request::Common qw(POST);
use LWP::UserAgent;
my $url = 'http://xxx.xxxx.xxx/somewhat/bla/bboard/newthread.php';
my $ua = LWP::UserAgent->new;
my $res = $ua->request(POST $url, [action => 'send', boardid => 4]);
Hope this helps.
gav^