I followed the set-up instructions (enable and make visible the filesystem repository; then in the data directory, add subfolders to the /repository folder, upload files with appropriate read permissions; then add repository on the "Configuration for file system repository" page).
Everything looks fine: my list of repositories shows up under "Repositories instances of the site."
But my folders (which show up in the file picker) always show up empty - even though I have uploaded test files (images, a .txt file, etc.). After the AJAX graphic spins, I get a "No files available" message.
Incidentally, the folder name that shows in the file picker is 'Root'. (See attached image.)