Can't install Xamarin Forms in a Xamarin Portable Project

'Xamarin.Forms 1.3.0.6292' already installed.
Adding 'Xamarin.Forms 1.3.0.6292' to Astig.Portable.
Could not install package 'Xamarin.Forms 1.3.0.6292'. You are trying to install this package into a project that targets 'portable-net45+win+wp80+Xamarin.iOS10+MonoAndroid10+MonoTouch10', but the package does not contain any assembly references or content files that are compatible with that framework. For more information, contact the package author.

I can't seem to add Xamarin Forms to a new Xamarin Portable Class Project? I created a new Xamarin Shared in the beginning and decided I want to mix it with PCL. Does anyone know why?