Estou recebendo um erro NODATA ao tentar atualizar

Estou recebendo um erro NODATA ao tentar atualizar

quando eu corro

sudo apt-get update 

este é o último erro de linha que recebo

E: GPG error: http://viewizard.com debian/ InRelease: Clearsigned file isn't valid, got 'NODATA' (does the network require authentication?) 

Isso está sendo executado no Ubuntu 13.10.

Este é meu sources.list:

# deb cdrom:[Ubuntu 13.10 _Saucy Salamander_ - Release amd64 (20131016.1)]/ saucy main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://us.archive.ubuntu.com/ubuntu/ saucy main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ saucy main restricted

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

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ saucy universe
deb-src http://us.archive.ubuntu.com/ubuntu/ saucy universe
deb http://us.archive.ubuntu.com/ubuntu/ saucy-updates universe
deb-src http://us.archive.ubuntu.com/ubuntu/ saucy-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://us.archive.ubuntu.com/ubuntu/ saucy multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ saucy multiverse
deb http://us.archive.ubuntu.com/ubuntu/ saucy-updates multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ saucy-updates multiverse

## 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://security.ubuntu.com/ubuntu saucy-security main restricted
deb-src http://security.ubuntu.com/ubuntu saucy-security main restricted
deb http://security.ubuntu.com/ubuntu saucy-security universe
deb-src http://security.ubuntu.com/ubuntu saucy-security universe
deb http://security.ubuntu.com/ubuntu saucy-security multiverse
deb-src http://security.ubuntu.com/ubuntu saucy-security 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 saucy partner
# deb-src http://archive.canonical.com/ubuntu saucy partner

## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
deb http://extras.ubuntu.com/ubuntu saucy main
deb-src http://extras.ubuntu.com/ubuntu saucy main
## Viewizard Games repository
deb http://viewizard.com/linux debian/

Responder1

Acho que você instalou a chave viewizard-gpg.ascdeeste URLcom estes comandos:

wget http://www.viewizard.com/linux/viewizard-gpg.asc
sudo apt-key add viewizard-gpg.asc

Mas não há mais chave nem repositório.

Remova essas linhas do seu sources.liste o problema será resolvido.

## Viewizard Games repository
deb http://viewizard.com/linux debian/

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