Try updating:
$InsertQuery->bindColumn("softwareID", "i", "".((isset($_POST["softwareID"]))?implode(",",$_POST["softwareID"]):"") ."", "WA_NULL");
to:
$InsertQuery->bindColumn("softwareID", "i", "".((isset($_POST["softwareID"]))?$_POST["softwareID"]:"") ."", "WA_NULL");