After Build, instantiate does not work

When I play my scene on Unity3D editor, everything is fine.

But when I build a PC standalone, or Webplayer, or Flash Player… my project does not instantiate prefabs from assets.

I just can view what my scene has static (background, static textures, etc…)

Any suggestion or idea?

var rocketClone : Rigidbody = Instantiate(rocket, transform.position, transform.rotation);

This doesn’t work for me after build