(J.K already knows this, but for anyone else that stumbles across this)
The issue is that Visual Studio 2015 has changes to the MeshContentTask. Also the version in that download has conditions for VS 11.0 and 12.0.
You also cannot copy the Visual Studio 2015 version directly without some changes (it is designed for a C++ project). I have attached an updated version to https://github.com/spazzarama/Direct3D-Rendering-Cookbook/issues/4 and will be committed to the repository once it has been made backwards compatible.