aqui estan los repos agregalos al sources.list y asi un update

deb http://ftp.cl.debian.org/debian/ lenny main
deb-src http://ftp.cl.debian.org/debian/ lenny main

deb http://security.debian.org/ lenny/updates main contrib
deb-src http://security.debian.org/ lenny/updates main contrib


si no te deja instalar, FORMAT :D