When installing Gentoo with my Asus A7N8X Deluxe motherboad, I couldn't get the network interfaces to work. I kept getting an error that said...
# ifconfig eth0 up
eth0: no link during initialization
Had to remove the forcedeth module to get 3c59x to work with my network interface.
Is this a problem during the installation, or on a running system? Did you try eth1 (IIRC, your mobo has 2 network connections) ? If installation problem, which livecd did you use?
Please reopen bug with requested info.