Loop Component: Riferimento a un oggetto non impostato su un'istanza di oggetto

Hi i’m trying to understand Loop plug in by Antonio Turriello, while i’m contructing the definition for the loop i’ve an error that says: “1. Solution exception: Riferimento a un oggetto non impostato su un’istanza di oggetto.”

What kind of problem is this and how i can solve it?

Here’s the .gh file
LoopComponentGH.gh (26.3 KB)

I’ve try to search some tutorials or lessons for this plug in but i found only examples, but i want to understand it deeply.

P.S. my timer component seem doesn’t work.
I think that’s because there’s an error in my definition.

Thank you!