Acess the properties of a MovieClip inside a Class

programming flash
1

I want to turn my previous background in a platform game with his alpha as 0, so i tried this:

CurrentStage.newRockyHills.alpha =0;

But it doens’t work. I also try to remove it (since it is the best option for memory), but it also doens’t work.

CurrentStage.removeChild(newRockyHills);

Any ideas?