Animation.Play gets MissingMethodException

this is the error

 MissingMethodException: UnityEngine.Animation.Play
 Boo.Lang.Runtime.DynamicDispatching.MethodDispatcherFactory.ProduceExtensionDispatcher ()
 Boo.Lang.Runtime.DynamicDispatching.MethodDispatcherFactory.Create ()
 Boo.Lang.Runtime.RuntimeServices.DoCreateMethodDispatcher (System.Object target, System.Type targetType, System.String name, System.Object[] args)
 Boo.Lang.Runtime.RuntimeServices.CreateMethodDispatcher (System.Object target, System.String name, System.Object[] args)
 Boo.Lang.Runtime.RuntimeServices+<Invoke>c__AnonStorey15.<>m__9 ()
 Boo.Lang.Runtime.DynamicDispatching.DispatcherCache.Get (Boo.Lang.Runtime.DynamicDispatching.DispatcherKey key, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
 Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.String cacheKeyName, System.Type[] cacheKeyTypes, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
 Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.Object[] args, System.String cacheKeyName, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
 Boo.Lang.Runtime.RuntimeServices.Invoke (System.Object target, System.String name, System.Object[] args)
 UnityScript.Lang.UnityRuntimeServices.Invoke (System.Object target, System.String name, System.Object[] args, System.Type scriptBaseType)
 PlayRunningAnimation.Update () (at Assets/PlayRunningAnimation.js:5)

Here is the script

     function Update()
 {
 if(Input.GetButtonDown("w"))
  {
  animation.Play("Default Take", PlayMode.StopALL);
  }
 }