You should check the console.
You have three issues.
1)
var camera = new Babylon.FreeCamera("camera1", new BABYLON.Vector3(0,0,-10), scene);
Replace Babylon with BABYLON, as Babylon is undefined.
2)
Do the same thing with
camera.setTarget(Babylon.Vector3.Zero());
3)
engiine.runRenderLoop… is undefined as well. It should be engine.
These issues are easy to catch if you check the developer console.