root=/dev/hda1/linux4/
This line suppose to reffer to where you install
kernel /boot/bzImage
: root=/dev/hda1

I don't think you need this two lines:
kernel /boot/bzImage
initrd /boot/initrd.gz
It belongs to syslinux and to boot cd.

I think you need is something like this:
title Linux(kernel2.4)
root (hd0,0)
kernel /boot/vmlinuz-2.4.26 root=/dev/hda1 ro ramdisk_size=100000 lang=us
savedefault
boot

You do install knoppix on hda1 right?