Although the Rio Receiver is a different product than the Empeg/Rio Car player, it shares some of the same troubleshooting steps with regard to ethernet. Please have a look at the Empeg Car FAQ entry on ethernet troubleshooting to see if any of those diagnostic steps can help you. Pay particular attention to the entries about 10/100 autosensing ports on newer model routers and switches, as those apply to the Rio Receiver and Empeg/Rio Car player equally.
Tony Fabris