the recordset is set to filter on a querystring variable named "idblogcomm", but this querystring variable does not exist when the insert form is submitted.
change the form tag code"
<form action="rispostecomm_Insert.php" method="post" name="WADAInsertForm" id="WADAInsertForm">
((isset($_POST["risposta"]))?$_POST["risposta"]:"")
to:
<form action="rispostecomm_Insert.php<?php echo((isset($_GET["idblogcomm"]))?"?".$_GET["idblogcomm"]:""); ?>" method="post" name="WADAInsertForm" id="WADAInsertForm">