Well, here we go... another version that uses the 'system' call (thanks, BrowserUk)...

use Win32::Process;
use Win32;
use Tk;

$cmd = "utest.bat";  # Spawned command

$mw = MainWindow->new( );
my $mylbl = $mw->Label(-text => 'Click Start')->pack( );
my $byebtn = $mw->Button(-text => "Exit", -command => sub { exit })->p
+ack( );
my $mybtn = $mw->Button(
               -text => 'Start', 
               -command => \&myjob
            )->pack( );
&reset_disp;
MainLoop;

sub myjob # ------------------------------
{
  &create_file_sys;
  &show_file_sys;
  &reset_disp;
}

sub create_file # ------------------------------
{
   $mylbl->configure(-text => 'Running...');
   $mw->update;

   Win32::Process::Create(my $ProcessObj,
                            "c:\\windows\\system32\\cmd.exe",
                            "cmd /c utest.bat del.me",
                           0,
                           NORMAL_PRIORITY_CLASS,
                           ".")|| die ErrorReport();
   
   $mw->update () while $ProcessObj->GetExitCode($exitcode), $exitcode
+ == 259;
}

sub create_file_sys # ------------------------------
{
   $mylbl->configure(-text => 'Running...');
   $byebtn->configure(-state => disabled);
   $mw->update;

   my $pid = system 1, 'utest.bat', 'del.me';
   waitpid $pid, 0;
}

sub show_file # ------------------------------
{
   $mylbl->configure(-text => 'Completed!', -foreground => 'red');
   $mw->update;

   Win32::Process::Create($ProcessObj2,
                           "C:\\windows\\system32\\notepad.exe",
                           "notepad del.me",
                           0,
                           NORMAL_PRIORITY_CLASS,
                           ".")|| die ErrorReport();

   $ProcessObj2->Wait(INFINITE);
}

sub show_file_sys # ------------------------------
{
   $mylbl->configure(-text => 'Completed!', -foreground => 'red');
   $byebtn->configure(-state => disabled);
   $mw->update;

   my $pid = system 1, 'notepad', 'del.me';
   waitpid $pid, 0;
}

sub reset_disp # ------------------------------
{
   $mylbl->configure(-text => 'Click Start', -foreground => 'black');
   $byebtn->configure(-state => active);
   $mw->update;
}
[download]

...and the (trivially) revised UTEST.BAT:

@echo off
:sleep -t 2
echo SLEEP IS DONE at %TIME% > %1
[download]

I'm still struggling a mite with the 'events' but I think I have something that works the way I want it to. An old thought of mine returns: if you can't get things to work, over-modularize it... and that's what I've done. At least it helps my understanding... and it does what I want.

As usual, the Monks have been very helpful... Thanks one 'n all :)