Hummm a lot of incorrect things here.
I think you renamed an important element (used one) in your HUD variables ("Hud & Boxes > User Variables")... Maybe "myHealth"?
You need it, so I'd suggest to rename it back to "myHealth":
Also, looks like you set one one of the element "4:var Image" type. The image type doesn't work in NESmaker, it's not yet correctly implemented. Don't use it... instead, use "0:var tiles" or "1:Hud asset".
Or if it was a mistake, and you don't need that element on our HUD, set its type to "none".