/store/phpbbservicesfolder. Is it different from the owner and groups of other files? If different, this folder should have the same owner and group as the other files in the store folder. The chown command can be used to change these
/store/phpbbservices/digestsfolder too and make sure it is consistent.
/ext/phpbbservices/digestsfolder. This is not obvious if you get the archive from GitHub, although it is in the README, but it's that way on the official archive on my website.
The extensions you already have installed (ads, boardannouncements, viglink) are all authored by phpBB and therefore their extension path is
Your tree was