Btw... a tip for Ubuntu users (which is blatantly obvious, but hey...) : At least on my setup, Ubuntu had installed the linux-kernel-headers, which is version 2.5.99-test7-bk-17. So I installed the proper headers for the kernel version I use (so for instance if you have linux-image-2.6.10-5-386 you should install linux-headers-2.6.10-5-386). Also make sure that the /usr/src/linux symlink exists. If it doesn't, load up the Terninal and type:
Code:
cd /usr/src
ln -s linux-headers-2.6.10-5/ linux
(with linux-headers-2.6.10-5 varying depending on the header version you have installed)