Dear Daniel
First of all I'd like to suggest you to rewrite the client in the next way :

#!/usr/bin/perl -w
use strict;
use SOAP::Lite;
use Tk;
use Data::Dumper;
my $main = MainWindow->new;
my $button = $main->Button(-text => 'go!', -command => \&get);
$button->pack;
MainLoop;

sub get { 
    my $soapObj = SOAP::Lite->uri('http://devzone:3004/My/Soapy')
    ->proxy('http://tako:3004');
    my $result = $soapObj->testy(); 

    unless ($result->fault()) {
        print "result : " . $result->result() . "\n";
    } else {
        print "faultcode : " . $result->faultcode() . 
    ", faultctring : " . $result->faultstring() . "\n";
    }            
}
[download]

I've checked that client and it works fine for my windows computer.
I guess there is a problem with network layer.
Try to run "ping tako" from your windows comp.
--
Alex