I have found the problem!
The object has a Tween in his create code, so it appears with a popping effect.
I dragged the object in the room via the room editor and the error occurred.
Then I instanced o_SharedTweener in the room creation code and I got all different errors.
So I removed the object from the room editor and instanced it in the room creation code and all worked fine!
No need to manually create o_SharedTweener
With previous versions I always placed some objects (eg. start button, etc..) in the first room via room editor drag n drop, and the tweens in their create event always worked fine.
If this behaviour is intended, I suggest to mention it in the documentation, when it will reach final stage.
Thank you for your support!!