I had a similar problem (
http://hutonggames.com/playmakerforum/index.php?topic=7682.0) with doing things to a global gameobject's specific FSM, so you could be encountering something similar.
If I'm dealing with prefabs that aren't always in the same scene, I usually use a broadcast all and make my event unique.
Have you checked during runtime that your global gameobject variable isn't losing your gameobject?
Also, another problem I've encountered in the past; When copy & pasting an action, even if the FSM listed is the right name, unless you select it again on the dropdown, then it doesn't find the target FSM. It really should blank the FSM target if the gameobject target has changed, but it doesn't for me, and this has lead to hours of trying to track down a problem that visually looks ok on the FSM.