The problem I've encountered is that I am using a keyboardEventListener to make a movieclip run around. As I'm a college student, I'm creating this for an assignment but we are forced to use as3 classes. When I run the code in the maintimeline, there is no problem. But when I try to access it from another class (with an 'Export for ActionScript' on the movieclip in question) I get an error he can't address the stage. this.stage.addEventListener(KeyboardEvent.KEY_DOWN, dostuff);