OK i've got a problem trying to compile a .tar.gz source file i have

lets call it afile.tar.gz

OK.. I've untarred it and moved to the directory that i need to be in, /home/user/afile

now with the installation guide that came with it it says to type 'make install' and i do this

well it goes through starting to compile it when i get this error

"Is the kernel-source package installed? KERNERLSRC does not point to a proper directory (/lib/modules/2.4.20/build). Stop."

I went to /lib/modules/2.4.20 and there is a file called build there. Being a noob i have no clue what to do here and any help is appreciated.

The kernel-source isn't included on the Slack 9.0-iso. Download and install it from the slackware-9.0/k directory.

Right, im beginning to get the idea that any compiling errors in slackware 9 are due to the fact that the kernel source isn't installed.