Sorry, maybe I don't fully understand, I am suggesting you replace

# email report back to sender showing the
# parts of original messages
open MAIL, ("|/usr/sbin/sendmail -t") || die "Unable to send mail: $!"
+;
print MAIL "To: $from\n";
print MAIL "From: root\n";
print MAIL "Subject: mime parser test\n\n";

print MAIL "Messege was contructed as follows:
\$from: $from
\$to: $to
\$subject: $subject

\$body: $body
";

close(MAIL);
[download]

with the MIME::Lite method. The issue I believe is that Outlook can't parse the email because it isn't being told explicitly how to deal with it via the "raw" sendmail type email construction method, and thereby defaults to its internal formatting rules.