Unity Play Mode

I'm new to development and I apologise if this is a newb question, but I am getting this error when I run my game in play mode in Unity. Does anyone know how to fix this error? 

NullReferenceException: Object reference not set to an instance of an object
OculusSampleFrameworkUtil.HandlePlayModeState (UnityEditor.PlayModeStateChange state) (at Assets/Oculus/SampleFramework/Editor/OculusSampleFrameworkUtil.cs:47)
UnityEditor.EditorApplication.Internal_PlayModeStateChanged (UnityEditor.PlayModeStateChange state) (at /Users/bokken/buildslave/unity/build/Editor/Mono/EditorApplication.cs:438)

Thanks heaps!