New try... I deleted the MD from the core and started from new. After installing and booting I get into the avWizard by pressing the button "2" on my keyboard.
Step 1: VGA is not working, the connector seems to be DVI. (that's why I have to press "2" to enter the wizard). I've chosen DVI with 1280x800.
Step 2: Static images
saving...creating...booting... the nVidia logo is there, now the X, now a black screen with the mouse, now the LMCE Launch Manager...uhuhuhhh...
I think the whole problem was my impatience. After finishing the avWizard I thought my laptop was stuck (I had some errors on the screen) and I just stopped it the hard way.
One step further... now it can't regenerate the skin for the orbiter... but that's the next step.
Thanks for your help