Virtualbox X-Server Problems

[develpoer23]

I use Gentoo as Guest in the Virtualbox (Host is Windows 7). I have installed it with the gentoo doc and all work.
Then I have installed the Virtualbox-guest-additions. This also works but I have problems with the X-sever.
At first I have done this:
Xorg -configure
X -retro -config /root/xorg.conf.new -> the server start, it works

cp /root/xorg.conf.new /etc/X11/xorg.conf
startx -> problems

Fatal server error:
Caught signal 11 (Segmentation fault) Server aborting

[quanta]

Have a look at /var/log/Xorg.0.log: