That's interesting. What kind of router do you have? Are you using UPnP on the router? If so, try disabling it and see if the messages go away. Do you have WEP or WPA enabled on the router? Double check that there isn't actually other people connected to your router. Last, try changing the channel, it could be a 2.4Ghz phone or other 2.4Ghz device (microwave) that is actually interfering.