Hello Valentin,
It seems like the error is caused by a bug in SystemModeler. We are looking into this.
However if you would like to simulate it without using quaternions, you could make it work by connecting the body to a Modelica.Mechanics.MultiBody.Joints.FreeMotion and then the freeMotion to the world component. See my attached model.
I hope this helps!
Thanks,
Markus
Attachments: