The code attached works for me and if it works for you then you've got other issues (mail server, environment, bad luck) ;-) One quick comment about the code snippet you posted - you're mixing camelCase ($mailContents) with underscore_case ($mail_headers). My advice is to pick one, and make sure you 'use warnings' at the top of you code.

One thing to _maybe_ try is using '\r\n' or just '\r'. Maybe your mailserver is wonky. :)

use strict;
use warnings;

use Mail::Mailer;

my $mailer = new Mail::Mailer 'smtp', Server => 'localhost' or die "Co
+uldn't create a mail object!\n";

my $mail_content = "Here is a first line.\nHere is a second line.\n";

my $mail_header =  {
    'Content-Type' => 'text/plain',
    To => [ 'xxxxxxxxxxxxxxxxxxxxxxx' ],
    From => 'xxxxxxxxxxxxxxxxxxxxxxx',
    Subject => 'Just some subject.',
};

$mailer->open( $mail_header );
$mailer->print($mail_content);
$mailer->close();
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