I wish I could say the same about it.. I just cant get it to work on my MK ii.
I keep on getting this error message, Tried the usual tricks but still the same..
forum: Canon EOS Digital Cameras
Did you download the new software?
I assume you did check you are on single focus point in the center and in one shot mode.
I also assume you checked to make sure the target is properly aligned.
Also, I found best result with really bright direct sunlight. Back when I first got the software about a year ago, I got a message that may be similar to the one you are seeing. I charged camera battery (to make sure it had good power to drive AF) and re-tried in better light and it worked.