translate forward dont work

Hi everyone!
I cant do transfom.Translate in a object.
Anyone knows why?
I want to transform forward, I use the script, for this. The object dont have any other script on it. And only have a animation to ratate, the wich dont affect the position keys.

Any idea?

var speed : float = 0.1;

function Update ()
    if (Input.GetKey(KeyCode.W))
        transform.Translate(Vector3.forward * speed);

//NOTE : Change the speed variable as you want