OpenVR Initialization Fails on Unity 5

I'm a Unity & Programming beginner.
The version is 5.5.1.

I want to use SteamVR and EditorVR in Unity 5, but I get an error and I can't press the play button.

• VR:OpenVR Error!OpenVR failed initialization with error code VRinitError_Init_PathRegistryNotFound: "Installation path could not be located (110)!"
• Assets/EditorVR/Workspaces/Project/Scripts/AssetGridItem.cs(246,13): error CS1061: Type `UnityEngine.Render' does not contain a definition for `motionVectors' and no extension method `motionVectors' of type `UnityEngine.Render' could be found.

When you open the script, it says:

 // Turn off extended render settings
    foreach(var render in m_PreviewObjectTransform.GetComponentsInChildren<Render>())
    {
        render.shadowCastingMode=UnityEngine.Rending.ShadowCastingMode.Off;
        render.receiveShadows=false;
        render.reflectionProbeUsage=UnityEngine.Rending.ReflectionProbeUsage.Off;
        render.motionVectors=false;
    }

Unity, there are no errors immediately after SteamVR download and
While creating objects and setting up cameras,
I noticed an error.

How can I solve this problem?

I look forward to your kind cooperation.