My Apple TV lets me play iTunes music on my TV (at the other end of the house) over Wi Fi connection but rented movies stall after a couple of minutes, saying there is no network connection. Having attempted to watch this way I am then forbidden to continue watching on my desktop as teh movie has been allocated to 'another device'. I'm only three minutes into Skyfall!
My iTunes library is on an external USB 2 drive. I'm wondering if it's failing to stream fast enough?
iMac, OS X Mountain Lion (10.8.2), 2.4 GHz Intel Core Duo 6GB SDRAM