First of all,... if you don't have to use Access, DON'T. For a nice converter from Access code to MySQL go to http://www.accessmysql.com
But ok,... the reason why your script isn't working is:
$MM_connNewsletter_DATABASE = "newslettertest.mdb";
That won't work,... some standard script for connecting to an access database is:
$dbname = "Customers"; //dsn name as in dsn system (ODBC configuration WIN32)
$username = "";
$password = "";
$con=odbc_connect($dbname, $username, $password); //don't change order
You have to go to your control panel and verify if the database exists in your computer's System DSN. Go To ODBC DATA sources, click System DSN and look if it's there. If not, add it,... speaks for itself I think.
Then the machine knows the database is there and you can call it with above's script. That's all, real easy.
Also take a look at http://www.phpbuilder.com/columns/siddarth20000228.php3