gettin null pointer exception

I am getting the following error, while a object is selected.

NullReferenceException

UnityEngine.Material..ctor (UnityEngine.Shader shader) (at C:/BuildAgent/work/ea95e74f6e5f192d/Runtime/ExportGenerated/Editor/Graphics.cs:1684)

GameDraw.GDManager.OnRenderObject ()

UnityEditor.DockArea:OnGUI()

Unity 4.2.2

Windows 8

also I have to change SelectionMode.Editable to UnityEditor.SelectionMode.Editable was getting compiler error.