Você precisa alterar oldstable
para lenny
.
Se você examinar o http-repository, não haverá pasta oldstable
. Daí o 404.
Se você não sabe por que tem certas coisas na sua lista de fontes (archive / oldstable), eu recomendo usar esta lista:
deb http://ftp.debian.org/debian/ squeeze main
#deb-src http://ftp.debian.org/debian/ squeeze main contrib non-free
# Security Updates
deb http://security.debian.org/ squeeze/updates main contrib non-free
#deb-src http://security.debian.org/ squeeze/updates main contrib non-free
# squeeze-updates, previously known as 'volatile'
deb http://ftp.debian.org/debian/ squeeze-updates main
#deb-src http://ftp.debian.org/debian/ squeeze-updates main
# testing or sid
#deb http://ftp.debian.org/debian/ testing main
#deb http://ftp.debian.org/debian/ unstable main
# Dotdeb Archive
#deb http://packages.dotdeb.org squeeze all
#deb-src http://packages.dotdeb.org squeeze all