1) The Dreamweaver recipes are for a discontinued product.
The recipes do not apply to the new "Payment Buttons for PayPal" extesnion.
2) eCart uses php code whether the items are static or not, so yes, you sill need an application server.
3) when a php page displays blank it means a php error has occurred but error reporting is turned of. you can add the following code to the page at line 1 to turn error reporting on:
<?php
error_reporting(E_ALL);
ini_set('display_errors','on');
?>
4) You can type quantity next to the quantity filed to accomplish this.
5) it will not allow fractions "1 1/2" for the quantity, but it will allow decimals "1.5"