It may make it past autodetection but it doesn't actually try to use graphics mode video until it tries to start X. It says 'entering runlevel 5' just before it tries to start X.
Try booting 'knoppix 2 lang=(whatever language you want)' which will start in console mode only. Then try 'startx' & see what happens. If this is where the problem begins, probably it is not setting up for you video card properly.
What is the video card?