[Grml] Grml2hd Xorg.conf screen blanks

[Mark]

grml live CD 0.8 final plus "apt-get update; apt-get install grml2hd"

At the xorg.conf step, if I say "yes," part of the screen goes black. 
The dialogs become impossible, although staying active.  (If only they
were movable with the mouse.)  If I say "no" everything works fine.

The blackness is top to bottom across ~40% of the horizontal, sort of
middle of screen.  nVidia GeForce card, but without nvidia drivers, just
the live CD with no special boot codes (except noswap).

When I ctrl-c out of the script, the screen is still bad, so I have to
reboot.

     M