Removed all codes from clips, placed code below in first frame main timeline

Removed variable from textfield and gave it an instance name of 'txt'.

Removed 'add bomb' button, added code for space bar.

Make sure when you test it, that you disable keyboard shortcuts.

Code:
var bomb = 5;
var armed = false;
var bombs = [];
var mc = null;
var keyListener = new Object();
hero.power = 4;
txt.text = bomb;

function makeBomb() {
        if (bomb > 0) {
                bomb -= 1;
                txt.text = bomb;
                mc = attachMovie("bomb", "bomb" + this.getNextHighestDepth(), this.getNextHighestDepth());
                mc._y = hero._y;
                mc._x = hero._x;
                mc.damage = false;
                bombs.push(mc);
        } else if (bomb <= 0) {
                trace("out of bombs");
        }
}
keyListener.onKeyDown = function() {
        if (Key.isDown(Key.SPACE) && armed == false) {
                armed = true;
                makeBomb();
        }
};
keyListener.onKeyUp = function() {
        if (Key.getCode() == Key.SPACE) {
                armed = false;
        }
};
function doUpDate() {
        if (Key.isDown(Key.LEFT)) {
                hero._x -= hero.power;
        } else if (Key.isDown(Key.RIGHT)) {
                hero._x += hero.power;
        } else if (Key.isDown(Key.UP)) {
                hero._y -= hero.power;
        } else if (Key.isDown(Key.DOWN)) {
                hero._y += hero.power;
        }
        for (var i in bombs) {
                mc = bombs[i];
                if (mc._currentframe == mc._totalframes) {
                        mc = bombs.splice(i, 1);
                        removeMovieClip(mc);
                        break;
                } else if (mc._currentframe >= 14 && mc.damage == false) {
                        if (hero.hitTest(mc._x, mc._y, true)) {
                                mc.damage = true;
                                trace("hit");
                        }
                }
        }
}
Key.addListener(keyListener);
hero.onEnterFrame = doUpDate;
HTH