do this yo
apt-get install kernel-source-2.6.8 <-whatever your ver. os
tar xvfj kernel-source-2.6.8.tar.bz2
ln -s /usr/src/kernel-sources-2.6.8 /usr/src/linux
just make sure you type the correct name of the kernel sources... i might have a dash wrong or a period wrong, but that's the layout you should go by
refer to my documentation to see my step by step guide...