The type or namespace name `WSA' does not exist in the namespace `UnityEngine.VR'. Are you missing an assembly reference?

I am using Unity 5.4.0f30HTP. in my old PC there was UntiyVR folder on following path "C:\Program Files\Unity HoloLens 5.4.0f3-HTP\Editor\Data\UnityExtensions\Unity\UnityVR" but in my new PC it is missing. and i guess that is why i am facing this error because of unavailability of UnityVR. So how can i overcome this error? Please help. Thanks in Advance