at line 1 of the page add an if statement that will set the fields to empty if PHP is selcted
from your previous example, it;s hard to tell if the field is named type or etype, but an example would be:
<?php
if(isset($_POST["type"]) && $_POST["type"] == "PHP") {
$_POST["hostname"] = "";
$_POST["Login"] = "";
$_POST["Password"] = "";
$_POST["Port"] = "";
}
?>