Bootloader Problem

[Hubertus Hiden]

Hello

I've installed Ubuntu yesterday and it looks really very very good - 
congratulations to all envolved in this.

A nifty little problem caused by the installation of ubuntu is that GRUB 
can't boot Win2k  anymore.
The message is:
    Booting Win2k/XP
    root (hd0,0)
    filesystem type unknown, partition type 0x7
    savedefault
    makeactive
    chainloader +1
after this the machine hangs
My partition table is:

hda1 / Boot / Primary / ntfs
hda5 / nc / logical / ntfs
hda3 / nc / logical / swap
hda6 / /  primary / ext3

Does anybody have an idea on what to do or where to look ?

Thanks a lot
Hubertus