Xbox 360 Cannot Find Wireless Adapter?

I have bought a linksys wga11b quite a while ago and it has always worked after configuring it. But for some reason when i try to connect to xbox live it says "To use a wireless Internet connection, connect an xbox360 Wireless Networking Adapter to your console." I am connecting it by an ethernet cable and the adapter is lit up saying its connected to the xbox 360, and also connected wirelessly to the router. What's going on here? Thanks.