I'm trying to compile a kernel module for a verdex motherboard, but I'm having a problem. I've installed gcc and make onto the verdex, but when running make on the module I want to make, I get "/lib/modules/2.6.21/build: No such file or directory". I can verify that /lib/modules/2.6.21/build doesn't exist, so that's ok, but what can I do to fix this problem?

I tried copying the ~/gumstix/gumstix-oe/tmp/work/gumstix-custom-verdex-angstrom-linux-gnueabi/gumstix-kernel-2.6.21-r1/linux-2.6.21 directory onto a usb memory stick and changing the /lib/modules/2.6.21/build entry in the makefile to /media/sdb1/linux-2.6.21. Now there's a lot of files not found and consequently a massive amount of other compile errors.

What am I doing wrong?