Movie Clip is a class but i can't call it's functions?

Hi,

I have a document class that assigns some button on the stage an function.

I have 2 cards on the stage. They have their own class.

From the buttons script i can trace the cards and i get:

[object MovieClip]

But I cannot call a function in them like

card_0.flipUp();

it errors:

TypeError: Error #1006: dimMe is not a function.

the card class is public starts out like:

       public class FlipCard extends MovieClip {

The function is public:

                    public function dimMe ():void {

                              this.alpha = .1;

                    }

Now, it's been a while since i have worked in flash so i am totally rusty. I sure hope this is something incredibly stupid i am forgetting!