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I am reading the instructions on conkeror site (and elsewhere) on how to install conkeror on Ubuntu (I am using Ubuntu 12_04 LTS) and it seems that the correct sequence is:

sudo apt-add-repository ppa:xtaran/conkeror
sudo apt-get update
sudo apt-get install conkeror conkeror-spawn-process-helper

The first step (apt-add-repository) seems to execute without a problem, giving the following output:

You are about to add the following PPA to your system:
Conkeror Debian packages for Ubuntu releases without xulrunner (i.e. for 11.04 Natty and later)
More info:
Press [ENTER] to continue or ctrl-c to cancel adding it

Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-  keyring /tmp/tmp.Re7pWaDEQF --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver hkp:// --recv CB29CBE050EB1F371BAB6FE83BE0F86A6D689050
gpg: requesting key 6D689050 from hkp server
gpg: key 6D689050: "Launchpad PPA for Axel Beckert" not changed
gpg: Total number processed: 1
gpg:              unchanged: 1

However, the apt-get update seems unable to fetch packages from the newly added PPA, with its output ending in:

Hit precise-security/restricted Translation-en
Hit precise-security/universe Translation-en
Err precise/main Sources                    
404  Not Found
Ign precise/main Translation-en_US
Err precise/main i386 Packages
404  Not Found
Ign precise/main Translation-en
Ign precise/main Translation-en_US
Ign precise/main Translation-en
W: Failed to fetch  /main/source/Sources  404  Not Found

W: Failed to fetch  404  Not Found

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

Accordingly, apt-get-install conkeror fails with:

mperdikeas@mperdikeas:~$ sudo apt-get install conkeror
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package conkeror

Any ideas what might be wrong ?

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up vote 4 down vote accepted

In your apt output there you have the following line.

W: Failed to fetch /main/source/Sources 404 Not Found

If you look at the ppa site ( you'll see they don't actually have any packages for 12.04

It looks like you'll probably have to try to get one of the nightly .debs to install with dpkg, or build it from source.

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Thanks, that's how it worked for me ... – MarcusJuniusBrutus Jun 8 '12 at 14:24

Looking like temporary server down issue .

try again after sometime else do this

open software-center > Edit> Software Sources > Ubuntu software > change your server to other best server and try again .

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