Now it has happend 2 or 3 times... my shutter simply freaks out.. it goes to 16000 and when I try to pull it down it works.. - a little.. and the it starts going up again... Like some invisible force is draging it to higher numbers..
And the shutterwheel is acting really strange: One time I pull it down, the speed goes down.. the next pull in same direction, the numbers go up.. Totally not logical!!!!
And this is all i Manual mode.. not auto-exposures and stuff.. It does it not for better exposure beacuse it happens in poor lighting so that my image turns BLACK (of course wiht a 16000 i shutter-speed next to a lightbulb)...

And the next second the camera is acting normal... just like nothing had happens..

arggg!!!

This does not happen to me.

Sounds like an issue with the camera. Contact Canon about repairs/new camera.