From what I can see, you're a little confused about the difference between pack and grid. In your snippet, you were using the pack manager. I wish that we could just switch managers by switching words, but we can't just yet.

Here's how it works with pack. I pared back a little. The push_button wasn't much help, so I left the callbacks out.

#!/usr/bin/perl

use strict;
use warnings;
use Tk;

my $mw = MainWindow->new;
$mw->Label( -text => 'Starcraft Strategy Generator' )->pack;
$mw->Button(
   -text => 'Generate Strategies'
   )->pack;
$mw->Entry->pack;
$mw->Checkbutton(
   -text => 'Use time limits?'
   )->pack;
$mw->Entry->pack;
$mw->Text(
   -width => 20, 
   -height=> 10
   )->pack;

MainLoop;
[download]

If you can post some more specific info, I can help you set it up using the grid manager.