Stage Problems

Hi Mastermind

First I have to thank you for this great package! I'm on to create a game with funny characters from my colleagues and we have a lot of fun with this.

Now I wanted to create more stages, but I have big problems with this. I tried to use the training room as template, but as soon as I insert new 3D Models, the characters are jiggling. I also tried to create a new stage with a cube as ground, a Plane (I set up the Layer) and own 3D models, but the problem is still the same. Either my characters are jiggling or the stage is not vissible. What I do wrong?

Can you please help or just post a picture with the right structure for a stage prefab?
Thanks

Marcel