W: attempt to set wrong option '//Acquire::http::Dl-Limit'
Já pesquisei no google, e informam que isto tem haver com o limite de banda. Enfim não sei como resolver esse problema.

O "W" no início da linha significa "warning", ou "advertência". Não é propriamente um erro.

Veja isso:

http://www.ubuntuka.com/rate-limit-for-apt-get-andor-aptitude/

Então eu não consigo actualizar pois quando rodo o upgrade aparece sucessivos erros.

retire isso (as duas barras):

//

deixe assim:

Acquire::http::Dl-Limit "VALOR_DESEJADO";

repita os passos:

# apt-get update
# apt-get dist-upgrade

Valeu pelas dicas, mas o problema não foi resolvido
root@murilo:/home/murilo# apt-get update
W: attempt to set wrong option '//Acquire::http::Dl-Limit'
Building old list of packages... [done]
Building old list of available updates... [done]
Building old list of watched packages... [done]
Atingido http://mirror.rit.edu squeeze-updates Release.gpg
Atingido http://http.us.debian.org squeeze Release.gpg
Ign http://http.us.debian.org/debian/ squeeze/contrib Translation-en
Ign http://http.us.debian.org/debian/ squeeze/contrib Translation-pt
Atingido http://backports.debian.org squeeze-backports Release.gpg
Ign http://backports.debian.org/debian-backports/ squeeze-backports/contrib Translation-en
Ign http://backports.debian.org/debian-backports/ squeeze-backports/contrib Translation-pt
Atingido http://www.debian-multimedia.org squeeze Release.gpg
Ign http://www.debian-multimedia.org/ squeeze/main Translation-en
Ign http://mirror.rit.edu/debian/ squeeze-updates/contrib Translation-en
Ign http://mirror.rit.edu/debian/ squeeze-updates/contrib Translation-pt
Ign http://mirror.rit.edu/debian/ squeeze-updates/contrib Translation-pt_BR
Ign http://mirror.rit.edu/debian/ squeeze-updates/main Translation-en
Ign http://mirror.rit.edu/debian/ squeeze-updates/main Translation-pt
Ign http://mirror.rit.edu/debian/ squeeze-updates/main Translation-pt_BR
Ign http://mirror.rit.edu/debian/ squeeze-updates/non-free Translation-en
Ign http://http.us.debian.org/debian/ squeeze/contrib Translation-pt_BR
Ign http://http.us.debian.org/debian/ squeeze/main Translation-en
Atingido http://http.us.debian.org/debian/ squeeze/main Translation-pt
Atingido http://http.us.debian.org/debian/ squeeze/main Translation-pt_BR
Ign http://http.us.debian.org/debian/ squeeze/non-free Translation-en
Ign http://http.us.debian.org/debian/ squeeze/non-free Translation-pt
Ign http://http.us.debian.org/debian/ squeeze/non-free Translation-pt_BR
Atingido http://http.us.debian.org squeeze Release
Ign http://www.debian-multimedia.org/ squeeze/main Translation-pt
Ign http://www.debian-multimedia.org/ squeeze/main Translation-pt_BR
Ign http://www.debian-multimedia.org/ squeeze/non-free Translation-en
Ign http://www.debian-multimedia.org/ squeeze/non-free Translation-pt
Ign http://www.debian-multimedia.org/ squeeze/non-free Translation-pt_BR
Atingido http://www.debian-multimedia.org squeeze Release
Ign http://backports.debian.org/debian-backports/ squeeze-backports/contrib Translation-pt_BR
Ign http://backports.debian.org/debian-backports/ squeeze-backports/main Translation-en
Ign http://backports.debian.org/debian-backports/ squeeze-backports/main Translation-pt
Ign http://backports.debian.org/debian-backports/ squeeze-backports/main Translation-pt_BR
Ign http://backports.debian.org/debian-backports/ squeeze-backports/non-free Translation-en
Ign http://backports.debian.org/debian-backports/ squeeze-backports/non-free Translation-pt
Ign http://backports.debian.org/debian-backports/ squeeze-backports/non-free Translation-pt_BR
Atingido http://backports.debian.org squeeze-backports Release
Atingido http://www.debian-multimedia.org squeeze/main i386 Packages/DiffIndex
Atingido http://http.us.debian.org squeeze/main Sources
Atingido http://backports.debian.org squeeze-backports/main i386 Packages/DiffIndex
Ign http://mirror.rit.edu/debian/ squeeze-updates/non-free Translation-pt
Ign http://mirror.rit.edu/debian/ squeeze-updates/non-free Translation-pt_BR
Atingido http://www.debian-multimedia.org squeeze/non-free i386 Packages/DiffIndex
Atingido http://http.us.debian.org squeeze/contrib Sources
Atingido http://http.us.debian.org squeeze/non-free Sources
Atingido http://http.us.debian.org squeeze/main i386 Packages
Atingido http://http.us.debian.org squeeze/contrib i386 Packages
Atingido http://http.us.debian.org squeeze/non-free i386 Packages
Atingido http://backports.debian.org squeeze-backports/contrib i386 Packages/DiffIndex
Atingido http://backports.debian.org squeeze-backports/non-free i386 Packages/DiffIndex
Atingido http://mirror.rit.edu squeeze-updates Release
Atingido http://mirror.rit.edu squeeze-updates/main i386 Packages/DiffIndex
Atingido http://mirror.rit.edu squeeze-updates/contrib i386 Packages
Atingido http://mirror.rit.edu squeeze-updates/non-free i386 Packages
Atingido http://mirror.rit.edu squeeze-updates/main i386 Packages
W: attempt to set wrong option '//Acquire::http::Dl-Limit'
Building new list of packages... [done]
Building new list of available updates... [done]
Building new list of watched packages... [done]
Building list of outdated packages... [done]

No new updates.
No new or removed packages.
No news in watched packages.
No outdated packages.
Lendo listas de pacotes... Pronto

Estranho não ter resolvido o problema, a configuração que passei era para ser inserida no arquivo /etc/apt/apt.conf (sem as duas barras), mas tem outra alternativa:

http://www.vivaolinux.com.br/dica/Limitando-a-taxa-de-download-do-Aptget

Não consegui pelo fato de não ter acesso a /etc/apt/apt.conf, rodo Kedit /etc/apt/apt.conf.d/70debconf e nada.

Não consigo editar o arquivo.

use o nano!

# /etc/apt/apt.conf

mova-se com as setas até a linha a ser modificada e para salvar e fechar tecle Ctrl+O e Ctrl+X

comece primeiro por esse arquivo, se não resolver você volta a ele e remova a linha referente a limitação de velocidade e passa para o outro arquivo citado na dica do xerxeslins.

* você não conseguirá rodar programa gráfico como root no KDE a menos que como usuário normal digite:

$ xhost +

ou que instale uma ferramenta chamada ' sux '.

Dica sobre o "sux" no Debian:

http://www.vivaolinux.com.br/dica/O-comando-sux/

A questão é que quando rodo nano /etc/apt/apt.conf não aparece nada para editar.