Those two updates obviously will not work the way you expected. They only get accessed after the downloading is completed. During the downloading, your GUI will just sort of "hang".

I have some script, sort of still "work in progress", but it helps you to attack this problem. What I did was that, I wrote the download part myself, instead of using any module so that I know the progress, and can update the progressbar every time after a portion of the downloading is done: (I am still working on it, so lots of stuffs are hardcoded, but the idea is certainly there. Take a look.)

use Tk;
use Tk::Progressbar;
use IO::Socket::INET;
use IO::Select;

use strict;
use warnings;

my $mw = MainWindow->new();
$mw->Button(-text => "Download", -command => \&download)->pack();
MainLoop;

sub download {
    my @documents;
    for (1..20) {
        push @documents, "song$_.Wma";
    }

    my $connections;

    my $selector = IO::Select->new();
    while (1) {
            if (my @readers = $selector->can_read(5)) {
            for my $reader (@readers) {
                my $line;
                if (my $length = sysread($reader, $line, 2048)) {
                    syswrite($connections->{$reader}->{"file"}, $line)
+;
                    $connections->{$reader}->{"received"} += $length;
                    $connections->{$reader}->{"progress"}->value($conn
+ections->{$reader}->{"received"} / $connections->{$reader}->{"length"
+} * 100);
                    $mw->update();
                } else {
                    close $connections->{$reader}->{"file"};
                    delete $connections->{$reader};
                    $selector->remove($reader);
                    close $reader;
                }
            }
        } else {
            if (my $document = pop @documents) {
                if (my $connection = IO::Socket::INET->new(Proto => "t
+cp", PeerAddr => "music.eting.cn", PeerPort => 80)) {
                    binmode($connection);
                    $selector->add($connection);
                    print $connection "GET http://blah.com/$document H
+TTP/1.1\r\nHost: 0.0.0.0\r\n\r\n";
                    my $line;
                    my $offset = 0;
                    while (1) {
                        my $len = sysread($connection, $line, 2048, $o
+ffset);
                        print $line;
                        if ($line =~ m/\r\n\r\n/) {
                            last;
                        } else {
                            $offset += $len;
                        }
                    }
                    $line =~ m/Content-Length: (\d*)/;
                    print "$1\n";
                    $connections->{$connection}->{"length"} = $1;
                    my $file;
                    open $file, ">", $document;
                    binmode($file);
                    $line =~ m/.*?\r\n\r\n(.*)/s;
                    syswrite($file, $1);                
                    $connections->{$connection}->{"received"} = length
+($1);
                    $connections->{$connection}->{"file"} = $file;
                    $connections->{$connection}->{"document"} = $docum
+ent;
                    my $frame = $mw->Frame()->pack();
                    $frame->Label(-text => $document)->pack();
                    $connections->{$connection}->{"progress"} = $frame
+->ProgressBar(
                        -width => 20, -length => 200,
                        -anchor => 'w',
                        -from => 0, -to => 100,
                        -blocks => 1,
                        -colors => [0, 'green'])->pack();
                    $mw->update();
                }
            } else {
                                unshift @documents, $document;
            }
        }
    }
}
[download]