Can anyone tell me why the little icon in the bottom right corner of iTunes disappears after I stop AirTunes sending my music to my (jailbroken with Seas0npass) Apple TV2?

The sharing works just fine until I only want it playing from my PC (running Windows 7). I have to reboot the modem every time to get the AirTunes icon back. I don't have to restart the Apple TV or Windows or even iTunes (running latest version I reboot the modem and the icon comes back.

Any thoughts would be appreciated!