Angular2 - unit testing with karma, system module option

I don't understand this situation: I'm working on a ng2 boilerplate with unit testing. (Repo: http://ift.tt/2bprTM3)

When I changed module option from commonjs to system in tsconfig.js, karma is not working anymore ... it return with this empty error:

Chrome 52.0.2743 (Windows 10 0.0.0) ERROR
  {
    "originalErr": {}
  }

I don't know how resolve this... there aren't any error detail. Someone have some idea? thanks.