In Universal Email, it looks like you are using the ID column from the recordset for the TO address:
$RecipientEmail = "".$row_application["id"] ."";include("WA_Universal_Email/WAUE_application_1.php");
} while ($row_application = mysql_fetch_assoc($application));
the ID column will likely contain a Unique ID number for the record, you should select the column that contains the email address instead.