I have a DLink DI-604 (I think) Router/Switch that is 10/100baseT autosensing. If I plug my Rios into this switch, they WILL NOT WORK, no link light. They work fine if and only if I plug them into my 10baseT hub, which is connected to the switch with an "uplink" cable.
So, check your link lights (both ends). Could be you could force the port on your switch to 10baseT, or you might even have a 10baseT hub you can try?