PHPMailer-ML Bug with PHP 5.4

This has taken hours to locate the source of the error. Even worse, the worx people do not have a forum any longer. I have posted a bug report on the source code website, but PHPMailer-ML has not been touched in a very long time. I am hopeful that someone other than me might benefit from this information.

What version of the product are you using? On what operating system?
PHPMailer 5.2.4
PHPMailer-ML 1.8.1

Please provide any additional information below.
This took hours to debug. PLEASE fix in the source for others. In PHP 5.4, session_register has been removed (see http://www.php.net/manual/en/migration54.incompatible.php)
The call is still being made in index.php (2x), acp-ml/index.php (3x), and subscribe.php (2x).

Simply change the calls to be of the syntax:
$_SESSION["return_msg"]

I would point you to the line numbers, but my version is not the standard, and a quick search of the files will rapidly show the line numbers needing this simple change.