Hello,
Thanks for the quick reply.
Something very strange happens when I add the code you gave in wp-config.php.
After adding it the problem with the blank white screen in theme settings is fixed and gives me to edit.
Also the problem with the error that gave it in “Theme Setup” disappeared after adding the code to enable debugging in WordPress.
But the problem with Chield Theme still remains.
After activating the “Chield Theme” something happens and the logo disappears on the first page which I think is not a big problem. But also the footer is not centred and the forum is missing all sidebars or the forum just becomes full width.
I also went through all folders and subfolders in detail but I don’t find debug log!