Mac Pro Cannot Connect to Netopia Cayman 3346 Router

I have 2 Macs and 2 Windows Machine at home all connected via an ethernet usb hub to a Cayman 3346 Netopia router. None of the Macs or PCs have any trouble connecting to the internet. However, I just got a new Mac Pro and anytime I start up the machine with ethernet plugged in it just hangs. If I start up without ethernet plugged in it starts up fine (it is connecting via DHCP though I have tried it with a fixed IP address, as well - same results). If I then plug in ethernet after the startup, I am able to connect briefly to the internet but then any network action causes the Mac to hang. I'm using 10.4.8. Does anyone else have this happening or any ideas on how to fix this. I have taken the Mac Pro to my office and connected via ethernet with no issues so it does appear it has soemthign to do with my router and the Mac Pro specifically. Grateful for any help.