Well, the kernel and the module MUST be matched exactly. I never have problems because I always build my own kernels from source and build in the drivers I need (I hardly ever use modules unless it's absolutely necessary... e.g. nvidia binary graphics drivers). For example, if your kernel is edited to change even one setting (the SAME exact kernel version, just configured a bit differently), then the module may not work. The kernel and module MUST be built off the exact same source tree.
Try this:
modprobe forcedeth
(does this give an error or does it seem to work?)
now do:
lsmod | grep -i eth
See if the forcedeth module is present
If it gave no errors and shows up on lsmod, then the module is fine, and you just need to properly configure the ethernet card. If it does not show up or gave an error on modprobe, then we need to get you the right module.
Also, post the output of "dmesg | grep -i eth"