/lib/modules/<kernelversion>/build
is simply a symlink to
/usr/src/<kernelversion>
Here's how to fix this:
Get the source for the kernel, if you don't have it. (check /usr/src/ to see.)
Once you've got it, untar it in /usr/src with
tar xjvf <kernelversion>.tar.bz2
Now, simply create that symlink.
ln -s /usr/src/<kernelversion> /lib/modules/<kernelversion>/build
Where <kernelversion> would be something like linux-2.4.22
Now, try again
(You need the kernel sources, usually, to compile any kind of driver module.)
-Shade