I'm trying to automate my program to submit this form by pressing the "Calculate Time Only" button.

use WWW::Mechanize; 



open(OUTFILE, '>c:\Perl output.txt') or die "Can't open output.\n";
open(UPSOUT, '>c:\Perl UPSoutput.txt') or die "Can't open output.\n";
$url = "http://wwwapps.ups.com/calTimeCost?loc=en_US&WT.svl=SubNav";

my $mech = WWW::Mechanize->new();  
$mech->get($url);

$form1 = "form1";
    $mech->form_name($form1);



$mech->set_fields(
    origPostal =>"53213",
    destPostal =>"60056",
    );

    $mech->field("transitTimeOnly", "Calculate Time Only");


$mech->submit($form1);

my $results2 = $mech->content;
print OUTFILE $results2;

die;
[download]

I get no errors, but the content of $mech is still the initial page. Why can't I submit this? How do I get it to submit?