I've been using my NA7004 to stream music from my main pc using iTunes, via a BT homehub and Netgear wireless extender, controlling it with the Remote app on my iPad. It has worked perfectly for months, but a few days ago, when I went to connect, an error message flashed up on the iPad saying something about "this device is already being used by another user". I got the same message when I tried sending the music from iTunes at the pc end. Meanwhile, if i try accessing the music via the network server function of the NA7004, it just comes up "empty". Has anyone experienced something similar, and can they offer some trouble shooting tips on how to fix this?