Those aren't the errors -- they're just warnings. I know, I know, it says "build errors:", but if you look up higher, they're each tagged with a "warning:".
The errors are (or rather, the error is) that the drivers couldn't patch your i810_audio.c file, so the package creation failed (I think it should just be ignored, personally, but that may cause more problems on other systems).
Anyway, the nvnet driver built, so if you don't care about the audio driver, just copy that file (that is, nvnet.o) as root from /usr/src/redhat/wherever/it/is to /lib/modules/$(uname -r)/kernel/drivers/net/nvnet.o and do an /sbin/depmod -ae
(to make sure there aren't unresolved symbols somewhere). Then you should be able to add alias eth0 nvnet
to /etc/modules.conf and run depmod -ae again (you don't have to run depmod twice, but you do have to run it after changing modules.conf, and it's a good idea to also run it after first putting the kernel module in place).