Currently Being ModeratedOct 16, 2011 3:13 PM (in response to RonnyB)
Check that you are on the same network and that your Apple TV settings are correct. Also check for router problems. If you are connecting your Apple TV wirelessly, try an Ethernet connection instead as a test.
I have noticed that AirPlay and AirPlay Mirroring are a bit buggy, so try it over and over after reconnecting and or restarting.