SE Invader Script exception.

2015-05-31 15:50:05.609 - Thread:   1 ->  Exception occured: System.NullReferenceException: Object reference not set to an instance of an object.
   at System.Object.GetType()
   at Sandbox.Game.Components.MyRenderComponent.IsVisible()
   at Scripts.KSWH.Invaders.UpdateEnemies()
   at Sandbox.Game.World.MySession.UpdateComponents()
   at Sandbox.Game.World.MySession.Update(MyTimeSpan updateTime)
   at Sandbox.MySandboxGame.Update()
   at Sandbox.Engine.Platform.Game.UpdateInternal()
   at Sandbox.Engine.Platform.FixedRenderLoop.<>c__DisplayClass2.<Run>b__1()
   at Sandbox.Engine.Platform.GenericRenderLoop.Run(VoidAction tickCallback)
   at Sandbox.Engine.Platform.FixedRenderLoop.Run(VoidAction tickCallback)
   at Sandbox.MySandboxGame.Run(Boolean customRenderLoop, Action disposeSplashScreen)
   at SpaceEngineers.MyProgram.RunInternal(String[] args)
   at SpaceEngineers.MyProgram.Main(String[] args)