In the quest for more quality, functionality and ease of administration, the Lenny repositories have been converted to new repositories, that are managed by reprepro. Fortunately, the impact for you as a user is small. The URLs to the repositories have changed (a path component /debian was added), so please update your sources.list to make use of the following URLs:
deb http://debian.dev-zero.nl/debian lenny-backports main
deb http://debian.dev-zero.nl/debian lenny-custom main
deb http://debian.dev-zero.nl/debian lenny-experimental main
deb-src http://debian.dev-zero.nl/debian lenny-backports main
deb-src http://debian.dev-zero.nl/debian lenny-custom main
deb-src http://debian.dev-zero.nl/debian lenny-experimental main
However, the old URLs still work, and will be rewritten on the server to the new, correct location.
Reprepro also makes it easy to automatically sign the Release files. Because of that, a new GPG key has been created,which will be used to sign the repository from now on. If you run aptitude update on your DevZero-enabled servers now, you will see Aptitude complain about the keys:
W: GPG error: http://debian.dev-zero.nl lenny-backports Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 6C28A78FCE3CD5E4
To update the key, upgrade the debian-devzero-keyring package to version 2010.02.09. Aptitude will tell you that you are trying to install an untrusted package and ask you if you are certain about that. Of course you are 
There are two alternative ways to install the new key into Apt’s keyring. The first one is:
gpg –keyserver hkp://pgp.mit.edu –recv-keys CE3CD5E4
gpg –export CE3CD5E4 | sudo apt-key add -
And the second one is:
wget -q -O – http://debian.dev-zero.nl/devzero.asc | sudo apt-key add -
