Os repositorios indicados no arquivo sources.list pelo amigo do tópico, não estão mais disponiveis para a distro 10.10 maverick do Ubuntu. Para que você consiga acessar os repositorios dos pacotes para esta distro, faça o seguinte:
1 - Logue-se como root: 
sudo su
2 - Remova as listas de repositorios já baixadas: 
rm -r /var/lib/apt/lists/*
3 - Agora, abra o aquivo sources.list: 
gedit /etc/apt/sources.list
4 - Remova todo o conteudo do arquivo e adicione o que segue abaixo:
#
## Ubuntu 10.10 Maverick Meerkat.
#
### Espelho Oficial.
### Ubuntu 10.10 Maverick Meerkat (Main, Restricted, Universe, Multiverse).
deb 
http://old-releases.ubuntu.com/ubuntu/ maverick main restricted universe multiverse
#deb-src 
http://old-releases.ubuntu.com/ubuntu/ maverick main restricted universe multiverse
### Ubuntu 10.10 Maverick Meerkat (Updates).
deb 
http://old-releases.ubuntu.com/ubuntu/ maverick-security main restricted universe multiverse
deb 
http://old-releases.ubuntu.com/ubuntu/ maverick-updates main restricted universe multiverse
#deb-src 
http://archive.ubuntu.com/ubuntu/ maverick-security main restricted universe multiverse
#deb-src 
http://archive.ubuntu.com/ubuntu/ maverick-updates main restricted universe multiverse
### Ubuntu 10.10 Maverick Meerkat (Proposed Updates).
#deb 
http://old-releases.ubuntu.com/ubuntu/ maverick-proposed main restricted universe multiverse
#deb-src 
http://old-releases.ubuntu.com/ubuntu/ maverick-proposed main restricted universe multiverse
### Ubuntu 10.10 Maverick Meerkat (Backports).
#deb 
http://old-releases.ubuntu.com/ubuntu/ maverick-backports main restricted universe multiverse
#deb-src 
http://old-releases.ubuntu.com/ubuntu/ maverick-backports main restricted universe multiverse
### Ubuntu 10.10 Maverick Meerkat (Partner).
deb 
http://archive.canonical.com/ubuntu maverick partner
#deb-src 
http://archive.canonical.com/ubuntu/ maverick partner
### Espelho Brasileiro.
### Ubuntu 10.10 Maverick Meerkat (Main, Restricted, Universe, Multiverse).
deb 
http://old-releases.ubuntu.com/ubuntu/ maverick main restricted universe multiverse
#deb-src 
http://old-releases.ubuntu.com/ubuntu/ maverick main restricted universe multiverse
### Ubuntu 10.10 Maverick Meerkat (Updates).
deb 
http://old-releases.ubuntu.com/ubuntu/ maverick-security main restricted universe multiverse
deb 
http://old-releases.ubuntu.com/ubuntu/ maverick-updates main restricted universe multiverse
#deb-src 
http://old-releases.ubuntu.com/ubuntu/ maverick-security main restricted universe multiverse
#deb-src 
http://old-releases.ubuntu.com/ubuntu/ maverick-updates main restricted universe multiverse
### Ubuntu 10.10 Maverick Meerkat (Proposed Updates).
#deb 
http://old-releases.ubuntu.com/ubuntu/ maverick-proposed main restricted universe multiverse
#deb-src 
http://old-releases.ubuntu.com/ubuntu/ maverick-proposed main restricted universe multiverse
### Ubuntu 10.10 Maverick Meerkat (Backports).
#deb 
http://old-releases.ubuntu.com/ubuntu/ maverick-backports main restricted universe multiverse
#deb-src 
http://old-releases.ubuntu.com/ubuntu/ maverick-backports main restricted universe multiverse
### Ubuntu 10.10 Maverick Meerkat (Medibuntu).
## Instalação da chave GPG para o Medibuntu:
## sudo apt-get update && sudo apt-get install medibuntu-keyring && sudo apt-get update
deb 
http://packages.medibuntu.org/">
http://packages.medibuntu.org/ maverick free non-free
#deb-src 
http://packages.medibuntu.org/">
http://packages.medibuntu.org/ maverick free non-free
5 - Salve e feche o arquivo.
6 - Agora chame o apt-get: 
apt-get update
7 - No final, aparecerá a seguinte mensagem: Erro GPG: 
http://packages.medibuntu.org maverick Release: As assinaturas a seguir não puderam ser verificadas devido à chave pública não estar disponível. Essa menssagem é apenas um aviso, mas as atualizações ocorreram com sucesso. Caso não deseje vê-la, execute a seguinte linha: 
apt-get --allow-unauthenticated install medibuntu-keyring
e em seguida:
apt-get update
Tive esse mesmo problema! Acabei de resolver e estou postando minha solução para vocês. Espero que Ajude!!