update error in ubuntu 9.10

[skkmaths]

i get the following error when i give the command for update in terminal.i use ubuntu 9.10 ..


Reading package lists... Done
W: GPG error: http://ppa.launchpad.net karmic Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5A9BF3BB4E5E17B5
W: GPG error: http://ppa.launchpad.net intrepid Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 638ABCA0FA3A1271
W: GPG error: http://ppa.launchpad.net karmic Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B5115B98AA836CA8

please help me to resolve this problem ......................

[mikewhatever]

It's isn't exactly a problem, in the sense that the error doesn't prevent you form installing software from PPAs. If you trust the ppa owners, it doesn't really matter whether you add keys or not. If you want to add authentication keys for cosmetic, or other reasons, check out the link below.
http://ubuntu-tutorials.com/2009/05/14/add-ppa-key-to-your-apt-keyring/

[MelDJ]

try the link in my sig

[hopugop]

I was having the same trouble, it's solved now. Thanks! ;)