cron failure message

[Tapas Mishra]

CRON-APT RUN [/etc/cron-apt/config]: Sun Oct 10 04:00:01 IST 2010
CRON-APT SLEEP: 2472, Sun Oct 10 04:41:13 IST 2010
CRON-APT ACTION: 0-update
CRON-APT LINE: /usr/bin/apt-get update -o quiet=2
W: Failed to fetch
http://debian.adenu.ia.uned.es/apt/dists/lucid/main/binary-amd64/Packages.gz
 404  Not Found

E: Some index files failed to download, they have been ignored, or old
ones used instead.
To: root
Subject: CRON-APT completed on server2 [/etc/cron-apt/config]

CRON-APT RUN [/etc/cron-apt/config]: Mon Oct 11 04:00:01 IST 2010
CRON-APT SLEEP: 526, Mon Oct 11 04:08:47 IST 2010
CRON-APT ACTION: 0-update
CRON-APT LINE: /usr/bin/apt-get update -o quiet=2
W: Failed to fetch
http://debian.adenu.ia.uned.es/apt/dists/lucid/main/binary-amd64/Packages.gz
 404  Not Found

E: Some index files failed to download, they have been ignored, or old
ones used instead.
To: root
Subject: CRON-APT completed on server2 [/etc/cron-apt/config]

CRON-APT RUN [/etc/cron-apt/config]: Tue Oct 12 04:00:01 IST 2010
CRON-APT SLEEP: 2844, Tue Oct 12 04:47:25 IST 2010
CRON-APT ACTION: 0-update
CRON-APT LINE: /usr/bin/apt-get update -o quiet=2
W: Failed to fetch
http://debian.adenu.ia.uned.es/apt/dists/lucid/main/binary-amd64/Packages.gz
 404  Not Found

E: Some index files failed to download, they have been ignored, or old
ones used instead.

I am getting above message in cron.
It is daily failing.