It sound as though the module nvnet was not installed or the wrong version for the kernel was installed.
See if it is there by using list (2.4.x kernel): ls /lib/modules/`uname -r`/kernel/drivers/net/nvnet.o
If it's not there, you may have to get the right rpm and re-install it or extract nvnet from the tar ball and manually compile and install. There are multiple discussions in this forum on nvnet issues and extracting and compiling. Search on nvnet and make
Hope this helps - good luck.