I have been messing with mine for the last 4 hours, even downloaded the updated PC share manager from samsung. I have the right server and I can see my pics and music under the annoying box.
Got a Samsung UE46B7020 TV connected by LAN to a Zoom X6 wireless router and communicate with that via a wireless laptop running PC share manager 2.3. Network on the TV is set up and auto detected all the required addresses and ticked all the boxes. Whenever I select anything from Media Play on the TV I get the message "Request cannot be completed. MEDIA PLAY will return to the main screen".
Music, film and photo are all of the correct format. The only partial success I've had is viewing photo. I can see the folder with the title that I want to access but I get this error message over the top which prevents me accessing it. Any ideas folks?