insmod linuxfet with RH 7.1

I purchased two ethernet cards from Compusa - both "compusa brand."
The first card was recognized and worked like a charm, the second card
not so. lspci -v shows the first to be a realtek card, and the second
to be a via card. So I built the driver, linuxfet.o, but insmod and
modprobe give unresolved symbol errors.

To build linuxfet, I had to create a symbolic link in
/usr/src/linux-2.4 called "include" that points to /usr/include/linux,
which is where the kernel headers are located. Could that have caused
some sort of problem when I try to run insmod? I also tried using the
via-rhine.o driver, but insmod complains about the device not being
found, etc.

Has anyone seen this before? Is there a general strategy for
confronting insmod unresolved symbol errors? I also recall seeing a
file called moduledep, or moddep. Do I need to list any dependencies
for linuxfet.o in this file to handled the unresolved symbol issue?
If I can build the driver, I figure what I need is on my system
somewhere, but insmod just can find it.

Thanks for any help anyone can give me,
Derek