Hi,
yeah, it's odd, first thing I would do is put appropriate logs int he Unity console to be absolutly sure you are calling something, when you are sure you do, you can rule out the action, and concentrate on why calling this api doesnt' work. you log before a potential return, this might be the problem, make sure you log one ling above the call that is supposed to do something,.
use UnityEngine.Debug.Log() inside action so that they get outputed inside the Unity console, else it's logged inside the PlayMaker log.
Bye,
Jean