After completion I get redirected to the filled out checkoutpane and and the cart will not empty.

I have a problem with the completion of an order. After completion I get redirected to the filled out checkoutpane and and the cart will not empty.

While working on the e-mail template I made a mistake in my uc-order--customer.tpl so the mail did not work. As a surprise I was redirected to the "Thanks" page I made and the cart was emty! Whe I fixed the e-mail template the redirection stopped working properly again.

Log report:

Notice: Undefined index: cart_order in _paynl_order_update_status() (regel 263 van /home/karsijns2/domains/karsijns.eu/public_html/sites/all/modules/paynl/paynl.inc.php).

The line in the module:

$_SESSION['uc_checkout'][$_SESSION['cart_order']]['do_complete'] = true;

$goto = 'cart/checkout/complete';
break;

Strange thing is that it works properly as the mail has not been sent.

I am using:

• Ubercart 3.10
• Drupal 7.53
• Third party module for payment: Ideal payment by Pay.nl

Anyone?
I'm not a real php specialist so forgive my probable incompleteness in this.