Does anybody here have a Sony STR-DN1040 and can explain to me why when accessing my network HD via its menu interface, although I can see the file tree and access the various .mp3, FLAC files, nothing happens when I select any of them. They appear in the menu with a ? against them, which may be a clue, but the supporting documentation is sparse... When I try and access the unit using the Sony AudioRemote iPhone app to access the same files, it simply says "cannot play music"... any help appreciated!!!!

Many thanks in advance,
Pete