your recordset is filtered using a URL Variable.
the action of the form does not pass the URL variables, so the recordset is empty when the form submits.
change:
action="<?php echo (htmlentities($_SERVER["PHP_SELF"], ENT_QUOTES)); ?>"
to:
action="<?php echo (htmlentities($_SERVER["PHP_SELF"], ENT_QUOTES).(isset($_SERVER["QUERY_STRING"])?"?".htmlentities($_SERVER["QUERY_STRING"], ENT_QUOTES):""));?>"
that will include any URL Variables that are passed in when the page loads as a part of the form action.