I have the following set-up, The modem, where my telephone/internet connections comes into the house has also a router and wifi function. Both the Naim as well as the Qnap are directly wired with Ethernet cables into that router/modem. From that same router/modem I have a windows pc wirded connected, via a switch. from that switch the signal goes also wired to my home office where via another switch I have wired connection the the Mac where Media Centre 21 is running, using the Qnap as its music source.
I can access the Qnap from both the windows pc as well as the Mac without any problems. I actuall can see all the contents on the Qnap via the Mac, add files, delete files etc all without any problem If I add or delete files the Naim (or the Naim Ipad app) reflects what's on the Qnap.
However, very frequently Media Centre (and actually only Media Centre) does not "see" the Qnap and its data. It does not allow to make tag changes,(although the changes are seen on Media Centre as if being executed, but they have not been executed on the Qnap. This creates a data integrity problem between the Qnap and Media Centre, but that's not my main concern at the moment.
It also does not allow to play music or to rip a new cd. So at the moment I rip a cd into Itunes and then copy the Itunes files (who are residing on the Mac itself) onto the Qnap for playing.
So there may well be a network issue between the modem/router, the two switches, the Qnap, the Mac and the Naim, but so far it only shows or has effect on Media Centre.
hope this clarifies, as the issue is becoming quit annoying.