'cmake' is not recognised as an internal or external command

The error message means it cannot find cmake.
You can add its location to your path from the prompt like this:

set PATH="C:\Program Files (x86)\CMake 2.8\bin\";%PATH%

As @doctorlove mentioned above, the error message means it cannont find Cmake.

Note that quotes aren't needed in PATH environmental variables on Windows. So the above example on Windows would look like:

set PATH=C:\Program Files (x86)\CMake 2.8\bin\;%PATH% 

I had the same issue, and resolved it in this post.