Document does not exist

Hi all, i’m in a bit difficult situation and hope that someone here can help me out.
A colleague that left our company years ago created a webinterface with scriptcase 8.1 that is still in use right now but the customer that uses it had to change servers a week ago.

There is nobody left in the company that knows much about this so it wasn’t easy to set it up again but i managed to get it working, apart from one problem remaining.

The scriptcase webpages have a button to show a list of documents but when i click on a document i get the error that it doesn’t exist.
However when i look in the MySql table the document is present in the blob field, i can get it from mysql as .bin field and when i rename that to .pdf i can open it.

So i suspect there is a problem in the scriptcase config to retrieve the blob content to a pdf in the browser.
I have been reading similar topics and set the permissions on the _Lib folder.
The folder _lib\prod\third\wkhtmltopdf exists and contains files.
But in the scriptcase config the configuration for “PDF Server IP” doesn’t get saved, and “Authorization key to view the maps” is also empty.

Please advise on what to try next to get this problem solved, many thanks.