File list export app exports metadata from Spotlight index of OS X, if you try to get info for files on a network drive or any folder that spotlight index is not enabled (by default spotlight index is not enabled for network drives) the app will not return all the metadata about the files (only some basic like file name, date modified, date created, kind, size, path).
You can check if spotlight index is enabled for a folder with this terminal command:
sudo mdutil -s <folder path>
e.g. sudo mdutil -s /Volumes/music
This command will return "Indexing enabled." if index is enabled.
If not you can enable spotlight metadata index with this command :
sudo mdutil -i on <path to folder>
Then execute: sudo mdutil -E <volume path>
to rebuild the metadata
It may take some time to index all your files.
If you do this and then (after some hours if you have many files) you can run the File list export app, and get the metadata for all your files.