OK. I figured it had to be some kind of error. Of course, there is no official errata for BoED...
If the prereq for Holy Ki Strike is really Ki Strike (lawful) (basically, you have to get Sanctify Ki Strike), that's 10th level minimum *sheesh*. Sanctify Ki Strike is just about useless at 10th anyway. Pretty wimpy for 1 point of extra damage. I'm sure the creatures the Monk faces at 10th level are going to be quaking in their boots about that!
The prereq for Sanctify Ki Strike for Ki Strike (lawful) makes no sense. You need to be able to do lawful damage, yet the feat affects only evil beings, outsiders, and undead, none of which have to be chaotic (a lot of them are, but still...)
After reading the Sanctify Ki Strike feat again, I am convinced its only true purpose is so that you can get the far better feat, Holy Ki Strike. 2d6 > 1 or 1d4.