I've just remastered a KNOPPIX 3.4 CD that I had upgraded to the latest unstable packages. When I try to boot from the CD, the X server starts up and I can see the KNOPPIX background but it instantly exits and returns to the shell prompt. When I run startx, the result is the same. The shell prompt shows the error message: "X-Window session terminated with errors. Please check and retry /etc/init.d/xsession start."