After reading your post again, and your email that you sent.. I think I figured out what you're trying to say.
Are you using the "add to health bar" behaviour (or some other health bar behaviour), then for the object selecting a graphic in your scene? If so, then you can't select regular graphics as health bars, You need to add a health bar object to your scene.
To do this, drag the beaker icon off the dock and into your scene. From the pop up select "Health Bar". This will add a health bar object to your scene. Once you have the object added, you can then chagne it's graphic to make it more custom looking (note: health bars have two graphics, a container, and the actual bar).
Hopefully this was your issue.