If boot.ini is consulted, then grub is not in the MBR, but Windows standard MBR. Perhaps you installed Vista after Knoppix (Kanotix)?

Try to boot again from DVD and check whether the /dev/sda4 in in /boot/grub/menu.lst
If it is, then somehow grub stage 1 loader was phased out of MBR and you'll need to reinstall grub in MBR.

Do a:

# apt-get install grub-doc

and see ``3.3 Installing GRUB using grub-install'' chapter.

AFAIR, the image on Kanotix is under /boot, so you may need to use --root-directory=/boot to grub-install, but see the manual. I haven't tried it yet myself (this information is just because no one else replied), so be careful and read three times, or you might leave a non-bootable system after running grub-install.

In that case, just reboot from DVD. And DO BACK UP IMPORTANT FILES PRIOR TO ALL OF THIS! (sorry for shouting)

Marv