No, you're facing a white screen because I asked you to test it with this code modification (this code allow you to redirect your customer to your "thank you"/"order canceled" pages), you can revert it.
What I need is what Post Finance really send you, I checked your payment log file, and saw this :
result :Array
(
[NCERROR] => 0
[ORDERID] => 10013
[PAYID] => 25081400
[STATUS] => 5
)
The payment status is 5, it means that the payment is authorized but that you didn't received the money for the moment. What you have to do is to change the status of the transaction to 9 or 91 when the transaction will be done, through your Postfinance configuration screen :
So the Postfinance server will automatically notify your server which will change the status of your order regarding the postfinance notification.
Can you install this version of the Postfinance plugin, so that I can test it myself ? It seems like I don't have access to the "extension manager"