Correction, it is
possible to use IEEE 1394 for IPv4 networking, though it's not normal practice.
RFC 2734 gives the outline for such an implementation.
As for answering the OP, to fix this you just need to download/install the correct driver for your ethernet controller. What's the manufacturer/model of your motherboard? Or rather, what's the model of your computer?
Get back to me with that info and I'll provide a link to the driver.