No, it is ObjectReference.
Okay. Got some sleep and in my right mind now.

And yes, you're right. I've been working with a lot of base objects lately.
That was that first thing I tried, before even posting, and it still said that TurnOn() wasn't a function...
I had something similar going on which is how I learned about casting as scriptTypes. It means there's a problem with how your Catapult1 is defined. The compiler doesn't see Catapult1 as a CWCatapult. I would try re-creating the ObjRef parameter on your Scene script. Clear it's value and re-link it in the render window.
Could go a little further. Maybe attach a new, simple script with an OnLoad event that throws out a Debug.Trace. It could then fires .TurnOn(). At least you know there's not some lingering CW dependency.