use strict;
use diagnostics;
use warnings;
use WWW::Mechanize 'new';

my $mech = WWW::Mechanize->new();
$mech->get( 'http://tv.walla.co.il/?w=/2//353//2011-10-22/1' );
$mech = $mech->content( format => 'text' );
writeFile('del at will.txt',$mech);
system('del at will.txt');
exit;

sub writeFile
{
  my $filepath = shift;
  my $nwntnt = join("",@_);
  $nwntnt = "\x{feff}".$nwntnt; #utf8 char starter
  no warnings;
  do
  {
    open(TXT, ">:utf8",$filepath);
    #open(txt, ">",$filepath);
    print TXT $nwntnt;
    close TXT;
    if($! and
    ($! ne 'No such file or directory') and
    ($! ne 'Bad file descriptor')
    )
    {
      print 'Error writing to file: '.$!."\a\nPath: $filepath\nhit the
+ enter to continue"; <>;
    }
    else{$! = '';}
  }
  while($!);
}
[download]

Well, you did show us the code in question but didn't show us how you used pp to package it, however I'm not sure what your expectations are regarding the size of the executable generated. If you unzip the executable you can see everything which gets bundled up inside the package, the modules you use, their dependencies, the core modules, perl shared libs and so on. See The resulting files are huge! How can I reduce the size of the output file? from the PAR FAQ, and also PAR::Tutorial.

I used pp by entrering "pp mechanisePpTest.pl" (& nothing else) in my terminal.
Technically it seems to have all functions operational but the return value is very different

When I referred to "length" it was the length of the string returned by the code,
not the size of the pl & exe files.

Hope that helps ^^

You probably forgot to use the -x option (or -c option)