Hello Joerg, squeeze-lts on archive [1] has a Valid-Until header which makes apt complain.
Also, squeeze is still on security [2] and LTS is still on primary miror [3]. Regards [1]: http://archive.debian.org/debian/dists/squeeze-lts/Release [2]: http://security.debian.org/dists/squeeze/updates/Release [3]: http://ftp.debian.org/debian/dists/squeeze-lts/Release -- Mathieu Parent
