/etc/apt/sources.listを
deb http://ftp.jp.debian.org/debian/ sarge main
deb-src http://ftp.jp.debian.org/debian/ sarge main
deb http://security.debian.org/ sarge/updates main
deb-src http://ftp.jp.debian.org/debian/ sarge main
deb http://security.debian.org/ sarge/updates main
に変更。
# apt-get update
# apt-get -u dist-upgrade