Here is a simple generic example to get you rolling. In the thread, I count to a number ( defaults to 5 ). All you need to do is put your Net::Ftp or LWP code into the thread instead. The test count thing is to show you the main Tk gui is not blocking while the thread runs. This threaded example needs a simple improvement to close the thread when exiting by the window manager's close button.... that should give you something to work out on your own. (By the way, unless you really need Net::Ftp, I suggest using LWP to get your files, since you can setup a progressmeter for big files. Search groups.google.com for "LWP Tk progress" )

#!/usr/bin/perl
use warnings;
use strict;
use threads;
use threads::shared;
use Tk;
use Tk::ActivityBar;
require Tk::Dialog;

# setup thread before any Tk code
my $go;
my $die;
my $progress;
my $data,

share $go;
share $progress;
share $die;
share $data; 
 
$go = 0;
$progress = 0;
$die = 0;
$data = 5;  # example value to stop search at

my $thread = threads->new(\&do_work);


my $mw = MainWindow->new(-background => 'gray50');

my $lframe = $mw->Frame( -background => 'gray50',-borderwidth=>10 )
                  ->pack(-side =>'left' ,-fill=>'y');
my $rframe = $mw->Frame( -background => 'gray50',-borderwidth=>10 )
                  ->pack(-side =>'right',-fill =>'both' );

my $activity = $lframe->ActivityBar()->pack(-side => 'top',-anchor => 
+'n');


my $button = $lframe->Button(
    -text       => 'get_file',
    -background => 'lightgreen',
    -command    => sub { &get_a_worker } 
           )->pack( -side => 'top', -anchor => 'n', -fill=>'x', -pady 
+=> 20 );

my $text = $rframe->Scrolled("Text",
                   -scrollbars => 'ose',
                   -background => 'black',
                   -foreground => 'lightskyblue',
                   )->pack(-side =>'top', -anchor =>'n');

my $repeat;
my $startbut;
my $repeaton = 0;
$startbut = $lframe->Button(
    -text       => 'Start Test Count',
    -background => 'hotpink',
    -command    => sub {
        my $count = 0;
        $startbut->configure( -state => 'disabled' );
        $repeat = $mw->repeat(
            100,
            sub {
                $count++;
                $text->insert( 'end', "$count\n" );
                $text->see('end');
            }
        );
        $repeaton = 1;
    })->pack( -side => 'top',  -fill=>'x', -pady => 20);

my $stoptbut = $lframe->Button(
    -text    => 'Stop Count',
    -command => sub {
        $repeat->cancel;
        $repeaton = 0;
        $startbut->configure( -state => 'normal' );
    })->pack( -side => 'top',-anchor => 'n', -fill=>'x', -pady => 20 )
+;

my $exitbut = $lframe->Button(
    -text    => 'Exit',
    -command => sub {
        
          $die = 1;
          $thread->join;
          if ($repeaton) { $repeat->cancel }
          exit;
      })->pack( -side => 'top',-anchor => 'n', -fill=>'x', -pady => 20
+ );


#dialog to get file url---------------------
    my $dialog = $mw->Dialog(
        -background => 'lightyellow',
        -title      => 'Get File',
        -buttons    => [ "OK", "Cancel" ]
    );

    my $hostl = $dialog->add(
        'Label',
        -text       => 'Enter File Url',
        -background => 'lightyellow'
    )->pack();

    my $hostd = $dialog->add(
        'Entry',
        -width        => 100,
        -textvariable => '',
        -background   => 'white'
    )->pack();

  $dialog->bind( '<Any-Enter>' => sub { $hostd->Tk::focus } );

   my $message = $mw->Dialog(
        -background => 'lightyellow',
        -title      => 'ERROR',
        -buttons    => [ "OK" ]
    );

  my $messagel = $message->add(
               'Label',
        -text       => '       ',
    -background => 'hotpink'
    )->pack();



$mw->MainLoop;
#######################################

sub get_a_worker {
  
  #disable multiple thread starts
  $button->configure(-state =>'disabled');
  
  # here you can pass data to the thread thru a shared var,
  # like what value to search for
  #  $data = 5;  # simple example

  $hostd->configure( -textvariable => \$data);
  if ( $dialog->Show() eq 'Cancel' ) { return }


  $activity->startActivity();
  $go = 1; 

# start a repeater to watch shared vars
my $watcher; 
$watcher = $mw->repeat(10, sub{  
      if ($go == 0){
      $activity->configure(-value => 0);
          
           if ($progress == $data){
              $text->insert( 'end', "\t\t\t$progress\n" );
              $text->see('end');
             }
        $watcher->cancel;
        $button->configure(-state=>'normal');
        }
  
 });
 
}

##################################
sub do_work{
     $|++; 
    
    
    while(1){
       if($die == 1){ goto END }; 
      
       if ( $go == 1 ){

#do your hash search or whatever          

   foreach my $num (1..100){
           $progress = $num; 
           print "\t$num\n";
           if( $num == $data ){ $go = 0 }
           select(undef,undef,undef, .5);
          if($go == 0){last}
          
          if($die == 1){ goto END }; 
       }



       
    $go = 0; #turn off self before returning      
       }else
         { select (undef,undef,undef,.1 ); } #nap time
    }
END:
}
###############################################
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