Apple TV Streaming

Hi. I have recently bought Apple TV and cannot get it to sync with ITunes. I can access the ITunes store directly through the Apple TV and it does show on my imac. However, every time I try to sync I get an error message that port 3689 is not open. I have though followed the assistance on this, but to no affect.

My system is imac 20" - about 2.5 years old, Apple TV, macbook air and my ISP is BT Internet.

Incidently I also have problems using the imac superdrive with my macbook air. Again it all looks ok and you can see a disk in the imac from the air, but trying to access content results in a message that the drive has no media in it.

Any thoughts gratefully received.

this is really late but is the ATV wired connection or wireless?? I had the same problem as i thought I would wire the ATV into my network for greater speed but my mac mini could not see it. It only seems to work "wirelessley". Also try going into the setting and adding the computers there.