W: Falha ao buscar para geogebra

Quando eu comando sudo apt-get updateeu recebo

W: Failed to fetch http://www.geogebra.net/linux/dists/stable/InRelease  Unable to find expected entry 'main/binary-armhf/Packages' in Release file (Wrong sources.list entry or malformed file)

E: Some index files failed to download. They have been ignored, or old ones used instead.

Pode ser que o motivo tenha algo a ver com meu sources.list

# deb cdrom:[Kubuntu 14.04 LTS _Trusty Tahr_ - Release amd64 (20140416.1)]/ trusty main multiverse restricted universe

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty main restricted
deb-src [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty-updates main restricted
deb-src [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty-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 [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty universe
deb-src [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty universe
deb [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty-updates universe
deb-src [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty-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 [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty multiverse
deb-src [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty multiverse
deb [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty-updates multiverse
deb-src [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty-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 [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src [arch=amd64] http://de.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse

deb [arch=amd64] http://security.ubuntu.com/ubuntu trusty-security main restricted
deb-src [arch=amd64] http://security.ubuntu.com/ubuntu trusty-security main restricted
deb [arch=amd64] http://security.ubuntu.com/ubuntu trusty-security universe
deb-src [arch=amd64] http://security.ubuntu.com/ubuntu trusty-security universe
deb [arch=amd64] http://security.ubuntu.com/ubuntu trusty-security multiverse
deb-src [arch=amd64] http://security.ubuntu.com/ubuntu trusty-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 [arch=amd64] http://archive.canonical.com/ubuntu trusty partner
deb-src [arch=amd64] http://archive.canonical.com/ubuntu trusty partner

## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
deb [arch=amd64] http://extras.ubuntu.com/ubuntu trusty main
deb-src [arch=amd64] http://extras.ubuntu.com/ubuntu trusty main

### For R:
# deb [arch=amd64] http://cran.r-mirror.de/bin/linux/ubuntu trusty/
# deb-src [arch=amd64] http://cran.r-mirror.de/bin/linux/ubuntu trusty/
# deb [arch=amd64] http://ftp5.gwdg.de/pub/misc/cran/bin/linux/ubuntu trusty/
# deb [arch=amd64] http://cran.es.r-project.org/bin/linux/ubuntu trusty
# deb [arch=amd64] http://www.stats.bris.ac.uk/R/bin/linux/ubuntu trusty/
# deb [arch=amd64] http://cran.stat.ucla.edu/bin/linux/ubuntu trusty/
deb [arch=amd64] http://cran.rstudio.com/bin/linux/ubuntu trusty/

### For R-Extras:
# deb [arch=amd64] http://orange.biolab.si/debian squeeze main
# deb-src [arch=amd64] http://orange.biolab.si/debian squeeze main

### For the KDE Widget "Concise":
deb [arch=amd64] http://ppa.launchpad.net/bytr/concise/ubuntu trusty main
deb-src [arch=amd64] http://ppa.launchpad.net/bytr/concise/ubuntu trusty main
# Run: $ sudo add-apt-repository ppa:bytr/concise; sudo apt-get install concise

### For Virtualbox:
# deb [arch=amd64] http://download.virtualbox.org/virtualbox/debian trusty contrib
# deb-src [arch=amd64] http://download.virtualbox.org/virtualbox/debian trusty contrib

### For Dropbox:
# deb [arch=amd64] http://linux.dropbox.com/ubuntu trusty main
# deb-src [arch=amd64] http://linux.dropbox.com/ubuntu trusty main

### For Resilio:
deb [arch=armhf] http://linux-packages.resilio.com/resilio-sync/deb resilio-sync non-free

ou o que posso fazer para corrigir isso? Estou usando o Kubuntu 14.4.