1394 is your firewire port and has little to do with networking, although Windows considers it a networking device. If you install the chipset drivers for your system, the 1394 connection should be taken care of.
I am having the same problem after re-formatting my friend's Inspirion 8200
The device manager only lists the 1394 Net Adapter, and the only item that is flagged is the PCI Modem -- but there is no intention to connect via dial up and I know that he was able to connect via broadband before.
We've downloaded everything relevant for the Dell site, including the 3Com and -- after seeing this post -- the chipset drivers. Nothing seems to be making a diference.
The 1394 says it's connected, at a speed of 400Mbps, but there is no activity.
When I plug the ethernet cable in, the lights come on and it *seems* to recognize it. I have even -- based on the post of another user -- tried powering off, replugging everything in, and powering up again.
Did the restart after each new driver install...
OMG WHY WON'T THIS WORK?!?!?