Sample Framework 1.19.0 compilation error with Unity 5.6.4,

Hi, I'm new to oculus development and I'm trying to get to grips with Touch input.

I started my project with the built in oculus sdk that unity creates when enabling VR ( 1.19 ), and then I believe I installed the utilities as well. Since then, I've got head tracking working fine in my project and was looking for example usage for touch VR input.

After installing the Sample Framework 1.19.0 package (I've also tried to do it without the OVR folder selected), I'm getting a series of compilation errors:

ERRORS:

Assets/OVRInspector/Scripts/OVRInspector.cs(861,39): error CS1061: Type `Button' does not contain a definition for `interactable' and no extension method `interactable' of type `Button' could be found. Are you missing an assembly reference?

Assets/OVRInspector/Scripts/OVRInspector.cs(866,39): error CS1061: Type `Button' does not contain a definition for `interactable' and no extension method `interactable' of type `Button' could be found. Are you missing an assembly reference?

Assets/OVRInspector/Scripts/OVRInspector.cs(1177,24): error CS1061: Type `Button' does not contain a definition for `interactable' and no extension method `interactable' of type `Button' could be found. Are you missing an assembly reference?

Assets/OVRInspector/Scripts/OVRInspector.cs(1188,24): error CS1061: Type `Button' does not contain a definition for `interactable' and no extension method `interactable' of type `Button' could be found. Are you missing an assembly reference?