Character in the Center of Screen

OMG so giving the character some actionscript motion is wrong??

Please help me sir i am very new to actionscript programming sir, I can't figure it out

Do you mind to see my codes. I have two buttons for my character, Jump button and Move button that moves only ti the right..

var dy:Number = 0;

var gravity:Number = 1;

var canjump:Boolean = false;

hero.gotoAndStop('still');

hero.speed = 0;

hero.upval = 0;

right_btn.addEventListener(MouseEvent.MOUSE_DOWN, doRight);

jump_btn.addEventListener(MouseEvent.MOUSE_DOWN, doUp);

stage.addEventListener(MouseEvent.MOUSE_UP, doStill);

stage.addEventListener(Event.ENTER_FRAME,onenter);

function doRight(e:Event):void {

        hero.speed = 5;

        hero.scaleX = -1;

        hero.gotoAndStop('walking');

}

function doUp(e:Event):void{

        hero.upval = -20;

}

function doStill(e:Event):void {

        hero.upval = 0;

        hero.speed = 0;

        hero.gotoAndStop('still');

}

function onenter(e:Event):void {

        hero.x +=  hero.speed;

        dy +=  gravity;

        if (hero.y > 441.95) {

                dy = 0;

                canjump = true;

        }

        if (canjump) {

                dy = hero.upval;

                canjump = false;

        }

        hero.y +=  dy;

}