Receiving Flash TypeError when trying to add an actor to a list

Exactly as the subject states.

Attached is the error itself and the code it references on line 230.
If I deactivate the do every 'n' seconds event I get the same issue but on line 203, also attached.

I have an actor that just wanders around, when it enters a region, it's supposed to be added to a list and then attacked. It's from this tutorial: http://blog.publysher.nl/2012/05/stencyl-tower-defense-5-choosing-your.html
The actor is for sure in the Enemies group. I tested several iterations before adding it to a list...thoughts?

Under created event, set Enemies in Range to create new list.

List needs to be set before use.

http://www.stencyl.com/help/view/lists/

Oh wow, thank you so much! I can't believe it was that simple...oh well!