Tipo 'sudo' não é conhecido na linha 64 ! [RESOLVIDO]

Galera, eu to com um problemão!
Eu não concigo mais usar o comando "sudo"
Por exemplo, se eu jogar o comando "sudo apt-get install amsn" aparece a seguinte mensagem:

E: Tipo 'sudo' não é conhecido na linha 64 na lista de fontes /etc/apt/sources.list

Isso aconteçe com qualquer comando "sudo" que eu boto...

Esse problema apareceu quando eu estava seguindo este turtorial, mas parei logo no inicio... http://tuxlink.wordpress.com/2007/11/08/instalar-screenlets-en-ubuntu/

Por favor, me ajudem.
Vlw.

Só pra vocês verem, é assim que está a minha source list:

#deb cdrom:[Ubuntu 8.04 _Hardy Heron_ - Release amd64 (20080423)]/ hardy main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.

deb http://br.archive.ubuntu.com/ubuntu/ hardy main restricted
deb-src http://br.archive.ubuntu.com/ubuntu/ hardy main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://br.archive.ubuntu.com/ubuntu/ hardy-updates main restricted
deb-src http://br.archive.ubuntu.com/ubuntu/ hardy-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## universe WILL NOT receive any review or updates from the Ubuntu security
## team.
deb http://br.archive.ubuntu.com/ubuntu/ hardy universe
deb-src http://br.archive.ubuntu.com/ubuntu/ hardy universe
deb http://br.archive.ubuntu.com/ubuntu/ hardy-updates universe
deb-src http://br.archive.ubuntu.com/ubuntu/ hardy-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://br.archive.ubuntu.com/ubuntu/ hardy multiverse
deb-src http://br.archive.ubuntu.com/ubuntu/ hardy multiverse
deb http://br.archive.ubuntu.com/ubuntu/ hardy-updates multiverse
deb-src http://br.archive.ubuntu.com/ubuntu/ hardy-updates multiverse

## Uncomment the following two lines to add software from the 'backports'
## repository.
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
# deb http://br.archive.ubuntu.com/ubuntu/ hardy-backports main restricted universe multiverse
# deb-src http://br.archive.ubuntu.com/ubuntu/ hardy-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository. This software is not part of Ubuntu, but is
## offered by Canonical and the respective vendors as a service to Ubuntu
## users.
# deb http://archive.canonical.com/ubuntu hardy partner
# deb-src http://archive.canonical.com/ubuntu hardy partner

deb http://security.ubuntu.com/ubuntu hardy-security main restricted
deb-src http://security.ubuntu.com/ubuntu hardy-security main restricted
deb http://security.ubuntu.com/ubuntu hardy-security universe
deb-src http://security.ubuntu.com/ubuntu hardy-security universe
deb http://security.ubuntu.com/ubuntu hardy-security multiverse
deb-src http://security.ubuntu.com/ubuntu hardy-security multiverse

## Medibuntu - Ubuntu 8.04 “hardy heron”
## Please report any bug on https://bugs.launchpad.net/medibuntu/
deb http://packages.medibuntu.org/ hardy free non-free
# deb-src http://packages.medibuntu.org/ hardy free non-free

deb http://ppa.launchpad.net/gilir/ubuntu gutsy main universe #Gilir's screenlets packages and some stuff you shouldn't use

sudo apt-get update

Nossa, valeu mesmo.

^^