It works!!! Finally!
from zero to GNU/Linux in five minutes
It took me exacly 24 hours, to figure everything out.

the working cheatcode was: linux26 fromhd=/dev/hda8 ramdisk_size=100000 init=/etc/init lang=nl vga=791 initrd=minirt26.gz apm=power-off hda=scsi hdb=scsi hdc=scsi screen=1280x1024 home=scan myconfig=scan nomce

Thanks everyone for you help.

[EDIT]When i install Knoppix, I get the option where to install lilo: in the mbr or in the root-partition. (I want a multiboot system with WinXP). What should i choose? Note: all partitions are on one hard drive.

[EDIT]I chose mbr. The installation was succesfull and lilo works how it should.