It sounds to me like you need to learn about recompiling you kernel. The way that I would go about this would be to recompile the kernel with the Tulip driver built in. Have a look at the following:
It will seem scary at first, but just leave the things that are set the way they are. Find your way to the network devices section "Network device support" when doing a 'make menuconfig' then go to "Ethernet (10 or 100Mbit)" then under "EISA, VLB, PCI and on board controllers" you will see mention of "DECchip Tulip (dc21x4x) PCI support" and "Old DECchip Tulip (dc21x4x) PCI support". Try enabling the first one, rebuild the kernel and see what happends. If this fails then try the 'old' option.
The HOWTO explains it all far far far better than I could. Clearly once you looked though it the more specific questions will be answerable by the people on the forum.