And how is this exactly a BCMP issue?
Anyway, as ACES_HIGH said, you need identical installs to play.
And I'm afraid to say, but there isn't a 1.2 (or 2.1) version of KM, the 1.0 version is currently in (closed) beta.
Or do you mean something like Enemies of Life (I believe that is in 1.2)?
So, if you want to install KM, then you need to do a clean install, the patch, and then KM.