This folder is empty

Hi,

I just installed this module, created an directory listing node, gave it a name, pointed it to audio (a folder relative to Drupal's root), and put some files into this folder. All I'm getting is: This folder is empty. I'm operating as user #1 so Drupal's permissions do not matter at this moment.

Which directory permissions does The system file path to the directory require (in my case it's www-data, the web server), and which file permissions do the uploaded files reqire? In my case:

# ls -lah
-rw-r--r--  1 www-data www-data  12M ...
-rw-r--r--  1 www-data www-data  25M ...
-rw-r--r--  1 www-data www-data  44M ...

I tried to to configure the Download manager settings, but neither "Public" nor "Private" seem to have any effect.

What am I missing?

Thanks & greetings, -asb