If you used RH's automatic service update service, the newest version is 2.4.9-13. For whatever reason, the "up2date" function does not install the latest kernel at /usr/src/linux 2.4.XX or whatever. In fact, RH does not install the kernel code anywhere that I could find. I had the exact same issue.
You can check your version to be sure by typing:
I ended up downloading the latest kernel 2.4.17 and building my own from scratch. You can download the latest kernel from:
There are some good kernel HOW-To's at:
However, it is a pain because you have to configure the kernel yourself. If it is your first time (like it was mine this week), it is not easy.
I hope this has helped!