Payment confirmation page is being redirected to an error page. Really strange!

Hi.
I have a problem with the payment confirmation page is being redirected to an error page.
Let my explain.

I use OC 2.3.0.2.
I use "Quick Checkout - Best One Page Checkout Solution". I use Payson for my payments.

I attached a picture with 4 smaller images. What happens is:
* In checkout the information needed is filled in (image 1). Order is confirmed.
* A new page appears (image 2). Additional information for Payson is filled in.
* The next Payson page appears (image 3). Here you are supposed to confirm your purchase by clicking on "Sluför köpet" button.
However this page only appears for a fraction of a second. No time to confirm the purchase.
* Instead the page redirects to Error page (image 4).

I've tried without using Quick Checkout and instead using the OC standard checkout. The result is the same.

The Payson support can't explain what's causing the error.
To me it seems like in som weird way the page is redirected to an error page.

No error to be found in the OC error log.

Somebody has any idea what's causing the problem?
Thanks in advance!

Solved.
The problem with the payment confirmation page being redirected to an error page is solved.
I had to comment out a row in the paysonCheckout2.tpl file:
<!-- document.location='index.php?route=payment/paysonCheckout2/returnFromPayson&address_data='+JSON.stringify(address); -->