remote app won't connect to home sharing

Got friends an iPod Touch 4G and AppleTV earlier. At Christmas, I encouraged them to download and install the Remote app on the iPod so they could use it with AppleTV. Set everything up and turned on Home Sharing in iTunes on their pc, but when looking in settings window in AppleTV, keep getting a message to turn on Home Sharing, even though it's already ON. Tried closing and reopening iTunes, restarting computer, restarting app, even downloading the latest version of iTunes for Windows; nothing changes and Remote app still won't work.

Is there something I'm missing?

Thanks for any help! Remote app looks like it would make using AppleTV a lot easier than using the AppleTV remote control unit, so getting it to work would make things easier for them.