AppleTV has no analogue connections.
It has HDMI which can go to your TV or in theory to an AV receiver equipped with HDMI inputs.
Some HDMI amps/receivers and HDMI switches can cause glitches with AppleTV but it really depends on the particular device.
AppleTV also has optical out, so if you only wanted a connection for Dolby Digital or stereo feeds from the AppleTV you could connect AppleTV to teh TV via HDMI and also run optical to the amp.
Audio is output over HDMI and optical simultaneously.
I would also suggest to update the firmware as soon as you inbox it. I've bought three apple tv's in the last week (two for work, one for my house) and they gave hdcp connectivity errors when playing hd content over AirPlay. It said the cables were bad or the device didnt support hdcp but as soon as I updated the firmware all was well. The apple tv at my house has worked flawlessly over hdmi to my Yamaha receiver post update. BTW, the firmware update is around 500mb.