Error Physic module

Hi!
We have imported a sample with camera scroll and physic and we have this error:

Uncaught TypeError: Cannot set property ‘enabled’ of undefined
at __define (Global.js:1)
at Object.func (Global.js:7)
at Object.run (modular.js:85)
at Object._prepareFinished (CCGame.js:390)
at CCLoader. (CCGame.js:492)
at CCLoader.js:276
at utils.js:79

where line 1 is:

cc.director.getPhysicsManager().enabled = true where cc.director.getPhysicsManager() is null

where we wrong?
Many thanks!

Stefano