I'd have to debug this live. I can only imagine that the recordset isn't getting the correct bcc email address. That is the only thing that I can think of that would cause it to not send.
I would start by adding this below the recordset but above the email code:
<?php
if (isset($_POST["btnSend"]) || isset($_POST["btnSend_x"])) {
die("bcc email: " . $rsEnq->getColumnVal("MemEmail"));
}
?>
That would at least confirm if the email address was coming in from the recordset correctly or not.