I realize that just setting the redirect is not solving a problem at all.
I deleted the URL for redirecting.
The result of the test after I swtched the PHP code that you replied is;
"insert into orderdetails (DetailID,DetailOrderID,DetailProductID,DetailName,DetailPrice,DetailQuantity) values (Standard rudder,102,102,'Fin1-S',0,1)"
But if I update the UE code on "confirm.php" as you adviced, the page appears blank.
So at the moment it is kept as it was before (as "undefined").
For the checkout, I chose "no-payment-gateway" (is this what you were asking about?).
I haven't made any change to these check-out pages generated by e-cart except this confirm.php page.
The changes I've made are layout, ecart set session value (changed ## part: $_SESSION["eCartCheckoutForm_##"] = "".((isset($_POST["##"]))?$_POST["##"]:"") ."";)
, "submit order" button ( it stopped working so I replaced it with checkout button).
I realize that I completely messed this up...
Thank you for your patience.