Failed to fetch (Failed to download repository information)

[linuxsyst]

Update manger:

Failed to download repository information

Check your Internet connection.

W:Failed to fetch http://ppa.launchpad.net/mozillateam/firefox-stable/ubuntu/dists/natty/main/source/Sources 404 Not Found
, W:Failed to fetch http://ppa.launchpad.net/mozillateam/firefox-stable/ubuntu/dists/natty/main/binary-i386/Packages 404 Not Found
, E:Some index files failed to download. They have been ignored, or old ones used instead.


when I do this:
sudo apt-get update in terminal it also gives me this:
W: Failed to fetch http://ppa.launchpad.net/mozillateam/firefox-stable/ubuntu/dists/natty/main/source/Sources 404 Not Found

W: Failed to fetch http://ppa.launchpad.net/mozillateam/firefox-stable/ubuntu/dists/natty/main/binary-i386/Packages 404 Not Found

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

Can you help me please.

[dino99]

the "source" might not exist, so open synaptic third parties repo to uncheck or remove the "source" line, then update again