Instructions
Turn off the Wii. Disconnect and reconnect the USB hub adapter to the Wii. Plug the USB hub into a working wall outlet.
Turn the Wii on. Verify the light on the USB hub is lit and receiving power. Disconnect any Wii remotes connected to the second through fourth player slots. Plug the guitar's USB cable into the USB hub.
Start the Rock Band game. Once you've reached the Rock Band main menu, press the "Sync" button on the USB hub and guitar. The lights on the hub and guitar will flash temporarily and eventually stabilize. After this, the guitar should maintain its connection with the Wii. If not, you may need a replacement guitar or USB hub.