The best way indeed would be to have a loop that reads small chunks and then passes them on to the socket :

sub dl_file { 

    my $file = param('file');
    $file =~ s/^\.+//;
    $file =~ s/^\///;
    
    if (-e "$folder/$file") {
         open IN,  "$folder/$file" or die "Cannot open file $file, $!\
+n";
         my $filename = (reverse (split /\//, $file))[0];
         print header(-type=>"application/x-msdownload",
                  -attachment=>$filename,
                  -cookie=>[$cookie1, $cookie2]);

         my $data;
         binmode IN;
         while ( read(IN,$data,16384)) {
           print $data;
         }
         close IN;
    }
    else {
        print $top, h1('Error'), p('file not found.');
        print hr, a({-href=>"$me?command=MAIN"}, 'Back to Main'), $bot
+tom;
    }
}
[download]

perl -MHTTP::Daemon -MHTTP::Response -MLWP::Simple -e ' ;    # The  
$d = new HTTP::Daemon and fork and getprint $d->url and exit;#spider
($c = $d->accept())->get_request(); $c->send_response( new   #in the
HTTP::Response(200,$_,$_,qq(Just another Perl hacker\n))); ' #  web
[download]