Yet again, problem concerning the black screen of death.

[user unknown]

The allways cheap tip 'burn new cd' is mostly wrong.
Why should the screen turn black when starting the gui?

Try starting with "4" which means runlevel 4.
So if your options are "THIS AND THAT"
knoppix26 THIS AND THAT 4

This should give you a shelllogin.
Then you may start x11 with 'startx' and evaluate the logfile after crashing:

cat /var/log/XFree86.0.log