CS1061 error when installing google cardboard. Help please.

Hey guys I just installed unity on windows 10. I also followed the google cardboard sdk instructions to play their demo but I’m got this error when I tried playing it:

Assets/Cardboard/Scripts/Audio/CardboardAudioSource.cs(297,19): error CS1061: Type UnityEngine.AudioSource' does not contain a definition for spatialize’ and no extension method spatialize' of type UnityEngine.AudioSource’ could be found (are you missing a using directive or an assembly reference?)

Assets/Cardboard/Scripts/Audio/CardboardAudioSource.cs(287,21): error CS1061: Type UnityEngine.AudioSource' does not contain a definition for SetSpatializerFloat’ and no extension method SetSpatializerFloat' of type UnityEngine.AudioSource’ could be found (are you missing a using directive or an assembly reference?)

Here is what the code looks like:

/ Initializes the source.
private bool InitializeSource () {
if (id < 0) {
id = CardboardAudio.CreateAudioSource(hrtfEnabled);
if (id >= 0) {
CardboardAudio.UpdateAudioSource(id, transform, bypassRoomEffects, gainDb, spread, rolloffMode, sourceMinDistance, sourceMaxDistance, directivityAlpha, directivitySharpness, currentOcclusion);
audioSource.spatialize = true;
audioSource.SetSpatializerFloat(0, id);
}
}
return id >= 0;
}

// Shuts down the source.
private void ShutdownSource () {
if (id >= 0) {
audioSource.SetSpatializerFloat(0, -1.0f);
audioSource.spatialize = false;
CardboardAudio.DestroyAudioSource(id);
id = -1;
}
}

Cardboard requires Unity 5.2.1 or later, which has the new audio spatializer plugin system.