I tried your suggestion and I got the same error message.
Now it is possible that I do it in the wrong page or I miss something. Would you like confirm if in what page should I update the behavior?
In my rootfolder I have :
1) checkout.php page
2) confirm.php page
3) pp_confirm.php page
I updated the 1) checkout.php page and 3) pp_confirm.php page.
Q1) Are they the right pages to update?
Q2) Is there any safe way (except the Attachment zip file) I can send you the entire error message without any masking?
I am afraid to mask accidentally certain information that probably can help you to diagnostic the problem.