World Editor...mouse problem

Just trying to explor the map in the demo game with the world editor. But when I try to rotate the camera with the right mouse button and a mouse move, the camera take a 90 degre angle from the ground and stock like that. So it just like waking the head up alway looking to the sky. And when aI rotate again everything go very rapidly...

Stock with that, can't do mutch. Not able to select anything while always looking to the sky...

Same thing with any Camera/World Camera and Camera/Player Camera setting.

Same installation on another computer = no problemo ?????

Any idea