Debian used to provide a ... (08 Mar 2003)
Debian used to provide a very useful file called base2.2.tgz for potato. In it was a very basic, but runnable, Debian system from which you could install everything else. You can still get the one for 2.2, but there's no such file for 3.0. Instead you have a tarball containing the debs of all the critical packages. Which is nice, except that you don't have dpkg to install them.
So, converting them all the tgz's and unpacking them gives you something close to a base system, except that dpkg doesn't think that anything is installed. Trying to install anything (including dpkg) pulls in libc6, and the inst script requires that dpkg know about itself. But you can't pull in dpkg because that requires libc6...
In the end you have to install base2.2.tgz and upgrade it. Yay Gentoo, Boo Debian.