I can't speak to Mail::Mailer, as I've never used it. Have you tried Mail::Sendmail? I've used it on several Windows platforms (from 9x to XP), and it's always worked well. It's independent of any "mailer" executable, such as sendmail, etc. The following code works for me (and is pretty much taken straight from the POD):

use Mail::Sendmail;

my %mail = ( To      => "$emailAddys",
             From    => "whatever\@mail.edu",
             Subject => "$subject",
             Message => "@body",
               );
$mail{smtp} = 'smtp.mail.edu';

sendmail(%mail) or die "\nDoh! $Mail::Sendmail::error\n";
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Update: Added example code per the following request.

If things get any worse, I'll have to ask you to stop helping me.