Debian doesn't detect disks from Live CD

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http://unix.stackexchange.com – I've loaded from the USB stick with Debian Live CD on it to fix the MBR after a Windows installation. Suddenly I've found that fdisk -l shows nothing but the live USB itself. What would it mean? I've used this image: http://cdimage.debian.org/debian-cd/current-live/i386/iso-hybrid/debian-... (HowTos)