So I fresh installed Dokuwiki on Debian Stretch, using Jessie repository package (Stretch, don't have Dokuwiki package yet).
Then I go to "Administration" >> "Configuration Settings" >> try to configure some settings, but in the begining position of that page, it shows I might set my file permission wrong on system so settings in this page can not be changed.
I follow the "Setting up file permissions" page
https://www.dokuwiki.org/install:permissions
in official dokuwiki and set all necessary directory/file permission correct, but I found I still have this message displayed.
And later I found if I change permission of conf/
directory itself (in my case /etc/dokuwiki/), to have write permission for web process (in my case www-data), then this message will not occur again and the settings could be edit.
I think maybe the "Setting up file permissions" page is not clear enough, which should also mention conf/ directory itself should have write permission too? (Or if I'm wrong?)