Button Script issue, works in game mode not in build and run

this script is on my button GUITexture

    var rolloverTexture : Texture2D;
    var normalTexture : Texture2D;
    var noTexture : Texture2D;
    var Dragon : GameObject;
    static var thisGameStart : boolean = false;

    function OnMouseEnter(){
        if(thisGameStart==false){
        guiTexture.texture = rolloverTexture;
        }

    }
    function OnMouseExit(){
        if(thisGameStart==false){
        guiTexture.texture = normalTexture;
        }else{
            guiTexture.texture=noTexture;
        }
    }
    function OnMouseUp () {

            var TargetScript : DragonGameIntro = gameObject.GetComponent(DragonGameIntro);

            TargetScript.attack = true;

            thisGameStart = true;

            guiTexture.texture = noTexture;
    }

this script is on a dragon that circles until the button is clicked then moves toward the target located near the camera

 static var attack : boolean = false;
    var MoveTarget : GameObject;
    var MoveTimer : float = 0;
    var emitter1 : GameObject;
    var emitter2 : GameObject;
    var emitter3 : GameObject;
    var light1 : GameObject;

    emitter1 = gameObject.Find("OuterCore");
    emitter2 = gameObject.Find("InnerCore");
    emitter3 = gameObject.Find("Smoke");
    light1 = gameObject.Find("Lightsource");

    var FireSound : AudioClip;

    function Update () {

        if(attack==false){

            gameObject.transform.Rotate(0,.5,0);
            gameObject.transform.Translate(0,0,.3);

            emitter1.particleEmitter.emit=false;
            emitter2.particleEmitter.emit=false;
            emitter3.particleEmitter.emit=false;
            light1.light.enabled=false;

        }

        if(attack==true){
            MoveTimer++;

            is_breathingfire=true;

            if(is_breathingfire==true){

                PlaySound(FireSound);

                emitter1.particleEmitter.emit=true;
                emitter2.particleEmitter.emit=true;
                emitter3.particleEmitter.emit=true;
                light1.light.enabled=true;

            }   

            transform.LookAt(MoveTarget.transform);
            transform.position = Vector3.Lerp(transform.position,MoveTarget.transform.position,Time.deltaTime * .6);
            var Dist : float = Vector3.Distance(transform.position,MoveTarget.transform.position);
            if(Dist<4){
                NextLevel();
            }

        }

    }

    function PlaySound(currentSound){

        audio.PlayOneShot(currentSound);

    }

    function NextLevel(){

                Application.LoadLevel("ValleyLevel");

    }   

    function gameStart(){

                attack=true;

        }

When I test it in game mode the button does the rollover and on MouseUp the dragon breathes fire and moves toward the target object. When I do build and run the rollover works but the dragon just stops wherever he happens to be, no flames, no Lerp, no level open.

I can't belive that your setup work, even in "game mode".

 var TargetScript : DragonGameIntro = gameObject.GetComponent(DragonGameIntro);

in this line you try to get a reference to the DragonGameInfo script. I guess, you didn't tell us the script names, your second script is the "DragonGameIntro" script and is attached to this dragon GameObject.

But you search for it on your GUITexture! I think you wanted do something like this:

 var TargetScript : DragonGameIntro = Dragon.GetComponent(DragonGameIntro);

You don't use the Dragon-GameObject-reference at the moment, so maybe you implemented it later and forgot to change it in that line.