When i run
sudo apt-get update, i get the following error
W: GPG error: http://ppa.launchpad.net lucid Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 9BDB3D89CE49EC21.
I tried searching for it, but wasn't able to find anything helpful. What is the reason for this, and how can i fix this?
Edit1: I am using Linux mint 9.
sudo add-apt-repository ppa:mozillateam/firefox-stable/ubuntu, I was getting
gpgkeys: HTTP fetch error 7: couldn't connect to host, so i did according to this post. When I run
sudo apt-get update, it gives no errors. But, firefox 5 is still not installed. In my update manager when I try to install, it says "Fix broken packages first". In Synaptic manager there is an option of "Fix broken Packages", but it does nothing. What is going wrong here?
Edit3: Update is used to resynchronize the package index files from their sources, and Upgrade is used to install latest versions. So, I was forgetting about upgrade!