I can see both flac and mp3's from the denon GUI when using windows media player (I had to install a patch to be able to add flac files to my WMP library). The denon will only let me play the mp3's though, I think that is due to the fact the WMP does not natively support flac Like I mentioned above.

I wonder if the software used by the NAS200 can be downloaded and used without the NAS200....

-David