the email is using SpecialOffers recordset. This recordset is filtered on the Newsletter querystring variabel.
The querystring variabel is passed in when the Report_newsletter_Results.php first loads, but it is not passed again when the form submits so the recordset is not being filtered.
change the forms action to pass any querysting variabels:
<form id="form1" name="form1" method="post" action="<?php echo $_SERVER["PHP_SELF"]; ?><?php echo (isset($_SERVER["QUERY_STRING"]) && $_SERVER["QUERY_STRING"] != "")?"?".$_SERVER["QUERY_STRING"]:""; ?>">