unresolved symbols and cat version.h doesn't list extraversion

[Elmer E. Dow]

I'm a newbie having problems compiling a driver correctly. It indicates 
unresolved symbols which I'm taking to mean that there's a kernel header 
mismatch.

I recently upgraded from 2.4.20-21.9 to 2.4.20-31.9 with the help of a 
friend who downloaded the updates.

I checked to make sure that the kernel-source-2.4.20-31.9.i386.rpm is 
installed and it is, but cat /usr/include/linux/version.h responds with
#define UTS_RELEASE "2.4.20"
Note that the extraversion is not listed. The version is correctly 
listed in the Makefile.

There is a gzip file in /var/cache/yum/updates/headers called 
kernel-0-2.4.20-31.9.i686. Since it's not an rpm, I'm not sure how to 
tell if it was installed. I assumed that the kernel source rpm would 
have used this somehow when it was installed.

Any advice?