Here is my updated code:

#!/usr/bin/perl -w
use strict;


use WWW::Mechanize;

my $response = "";
my $m = WWW::Mechanize->new();
$m->agent_alias('Linux Mozilla');

#$m->get('https://msp.f-secure.com/web-test/common/test.html');
$m->get('http://alumni.nd.edu/s/1210/start.aspx?sid=1210&gid=1&pgid=3&
+cid=40');

printf("%s\n", $m->title());
$m->dump_forms();
$response = $m->submit_form(
    form_number => 1,
    fields        => {
        'cid_40$txtUsername'    => '<username>',
        'cid_40$txtPassword'    => '<password>',
    }
);



die unless ($m->success);

printf("response code is %s\n", $response->code);
printf("response message is %s\n", $response->message);
printf("response content is %s\n", $response->content);
printf("response header time is %s\n", $response->header('date'));
[download]

The above should be correctly parsing the response from the command. The only problem is that the response doesn't seem to indicate what is going on:

response code is 200
response message is OK
response content is (tons of binary data)
response header time is Wed, 13 Mar 2013 03:36:18 GMT
[download]

I can't figure out from the above what is going on. Does anyone have any hints/tips? Note that I get the above response even if I enter a deliberately incorrect username and/or password.

$m->res->dump; ## I AM DEBUGGING HERE
$m->content; ## DECODED CONTENT HERE, if gzipped, its gunzipped , etc
[download]

Is it because you are single quoting your username and password variables?