It took me a while to figure out what KE2/7/8 and KF1/2/3/4 meant and how to look it up on my SGS2. Once I did, the process was very easy.
I think adding the following information at the top of the first post will help a lot of people:
1.) The CF-Root process is dependant on your phone's particular kernel.
2.) The kernel on your particular Samsung Galaxy S II is dependent on build-date, geographic location, and brand.
3.) How to lookup the kernel name.
4.) How to associate the important letters in the kernel name with the appropreate CF-Root file download.