como instalo o synaptic?

[rafasnn]

Estou tentando instalar o synaptic no kubuntu 5.10 amd64 mas aparece um erro

rafasnn@notebook:/boot/grub$ sudo apt-get install synaptic
Lendo Lista de Pacotes... Pronto
Construindo Árvore de Dependências... Pronto
O pacote synaptic não está disponível, mas é referenciado por outro pacote.
Isso pode significar que o pacote está faltando, ficou obsoleto ou
está disponível somente a partir de outra fonte
E: O pacote synaptic não tem candidato para instalação
rafasnn@notebook:/boot/grub$                

o que pode ser?

[Magneto]

Atualizou tua lista de repositórios?

sudo apt-get update

[rafasnn]

dá erro com o apt-get update

[Magneto]

Pegou a lista aqui do fórum mesmo?Ou está usando a que vem com o Ubuntu?

[rafasnn]

estou usando a padrão

[Magneto]

Utilize esta aqui:

Abra o terminal e digite:

sudo gedit /etc/apt/sources.list

apague o conteudo e cole esse abaixo, depois de o apt-get update novamente.

## Este arquivo deve ser salvo como /etc/apt/sources.list
## Para tirar suas duvidas sobre Ubuntu e bater um papo
## com o pessoal visite: http://ubuntu.linuxval.org
## A comunidade Ubuntu Luso-Brasileira.
## Todas as linhas deste arquivo que começam com o
## símbolo "#" não serão interpretadas pelo Linux,
## pois são apenas comentários.

############# Este é o CD-ROM do Ubuntu #################
## Descomente caso queira instalar pacotes do CD
# deb cdrom:[Ubuntu 5.10 _Breezy Badger_ - Release i386 (20051012)]/ breezy main restricted
#########################################################

##########################################################
#### Repositorios oficiais do Ubuntu 5.10 - Breezy #######
##########################################################
## Softwares atualizados
deb http://archive.ubuntu.com/ubuntu breezy main restricted
deb-src http://archive.ubuntu.com/ubuntu breezy main restricted
##
## Atualizações e correções de bugs suportadas pela equipe
##
deb http://archive.ubuntu.com/ubuntu breezy-updates main restricted
deb-src http://archive.ubuntu.com/ubuntu breezy-updates main restricted
deb http://security.ubuntu.com/ubuntu breezy-security main restricted
deb-src http://security.ubuntu.com/ubuntu breezy-security main restricted
##
## universe - não-livres, alguns suportados pela equipe
##
deb http://archive.ubuntu.com/ubuntu breezy-updates universe
deb-src http://archive.ubuntu.com/ubuntu breezy-updates universe
deb http://security.ubuntu.com/ubuntu breezy-security universe
deb-src http://security.ubuntu.com/ubuntu breezy-security universe
deb http://archive.ubuntu.com/ubuntu breezy universe
deb-src http://archive.ubuntu.com/ubuntu breezy universe
##
## multiverse - não-livres, não-suportados pela equipe
##
deb http://archive.ubuntu.com/ubuntu breezy-updates multiverse
deb-src http://archive.ubuntu.com/ubuntu breezy-updates multiverse
deb http://security.ubuntu.com/ubuntu breezy-security multiverse
deb-src http://security.ubuntu.com/ubuntu breezy-security multiverse
deb http://archive.ubuntu.com/ubuntu breezy multiverse
deb-src http://archive.ubuntu.com/ubuntu breezy multiverse
##
## Backports - Pacotes importados de versoes mais novas - Brasil
deb http://archive.ubuntu.com/ubuntu breezy-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu breezy-backports main restricted universe multiverse

##########################################################
####################### ATENCAO ##########################
##########################################################
# Os repositorios abaixo nao sao oficiais do Ubuntu.     #
# Se quiser utiliza-los faca por sua propria conta e     #
# risco. Basta retirar o simbolo "#" no comeco da linha  #
# com o endereco do repositorio para ativa-lo. Salve o   #
# arquivo e feche-o. Em seguida execute o comando:       #
# sudo apt-get update                                    #
# Feito isso abra o gerenciador de pacotes e instale o   #
# programa desejado. Apos feito isto, edite novamente    #
# este arquivo e comente novamente a linha colocando o   #
# simbolo "#" no inicio da linha com o endereco          #
#                                                        #
# Utilizar repositorios do Debian pode incluir riscos    #
# Sempre que estiver com um repositorio nao-oficial      #
# ativado, NAO faca nenhuma das atualizacoes indicadas   #
# pelo ubuntu para nao misturar os pacotes debian/ubuntu.#
##########################################################

##########################################################
###### Repositorios NAO oficiais do Ubuntu 5.10  #########
##########################################################

################ Open Office 2.0 Final ###################
# deb http://people.ubuntu.com/~doko/OOo2/ ./
##########################################################

################## Codecs Multimidia #####################
##### Atencao: descomente apenas para instalar codecs ####
######### multimidia e depois comente novamente ##########
# deb ftp://ftp.nerim.net/debian-marillat/ etch main
##########################################################

######### Poucos pacotes, mas possui o Gaim-VV ###########
# deb http://people.debian.org/~smimram/debian/ unstable main
##########################################################

############## Skype e outros programas ##################
## Descomente para instalar algum programa específico e comente novamente.
# deb http://debian.neo.pl/wfmh/ unstable main contrib non-free
##########################################################

############ Plugins para o Gift (Apollon) ###############
# deb http://apt.cerkinfo.be/ unstable main contrib non-free
# deb-src http://apt.cerkinfo.be/ unstable main contrib non-free
##########################################################

###### Aqui voce encontra o libdvdcss para tocar #########
##### DVDs e o VLC (Player de video super compativel) ####
#deb http://download.videolan.org/pub/videolan/debian sid main
#deb-src http://download.videolan.org/pub/videolan/debian sid main
##########################################################