Well, it's still working. Here's the system that works (for me):

Seimens 4-port Ethernet Router (with Powerline capability)
Linux (Red Hat 9) server hooked into the router
2 Dell Badged Rio Receivers hooked directly into the router
--> 1 Receiver works through a 10/100 Gigafast 8-port switch
1 Dell Badged Rio Receiver hooked into the Powerline
--> Rest of network hooks into a Linksys 8-port Gigabit switch

Note: NOT possible to hook ANY Rio receivers into the Gigabit switch, and have them work (on either Broadcast or Multicast, but works 100% on Unicast).
Also, NOT possible to hook the server into the Gigabit switch, and have them work (on either Broadcast or Multicast, but works 100% on Unicast).

Wish I could use my server on my Gigabit network, but for now, this is what works....

-Dan