Sharing preference (system preference help?)?

may be your computer configured by admin using some scripts..

if yes, you cant do it..

if its you own comp and you are admin to it..

there 2 options..

1. reinstall you oparating system

2. go to registry find the value and change or use 3rd party software which reset your settings back..

The support article you were looking at is for rare cases where you had your AppleTV syncing to iTunes, but then it stops and you get a firewall message. I'm guessing from your question that you never got it working in the first place. Here's what you should check: 1. AppleTV has to be connected to your home network either wireless or ethernet. It uses this to access both iTunes and the internet. You can test the network connection by looking at some movie trailers in AppleTV. If they download go to #2 2. The first time you open iTunes after the AppleTV is on the network, it should detect it and ask you for a 5 digit code that will pop up on the ATV. If that's not happening, go to iTunes - Prefernces menu and make sure "look for ATV" is checked. The link below has other troubleshooting tips, but the ones above should work most of the time. Also, once you connect for the first time, you won't have any issues in the future.