repository probs

[squareyes]

Hi all,
am trying to install w32codecs, have added nerim, and when i do
asudo apt-get update I get as follows

squareyes at here:~$ sudo apt-get update
Password:
Get:1 http://au.archive.ubuntu.com breezy Release.gpg [189B]
Get:2 http://au.archive.ubuntu.com breezy-updates Release.gpg [189B]

<snip>


Hit ftp://ftp.nerim.net sid/main Packages
Hit ftp://ftp.nerim.net sarge/main Packages
Fetched 51.5kB in 17s (2958B/s)
Reading package lists... Done

W: GPG error: http://au.archive.ubuntu.com breezy-updates Release: The
following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu
Archive Automatic Signing Key <ftpmaster at ubuntu.com>
W: GPG error: ftp://ftp.nerim.net sid Release: The following signatures
couldn't be verified because the public key is not available: NO_PUBKEY
07DC563D1F41B907
W: You may want to run apt-get update to correct these problems
squareyes at here:~$
No point running apt-get update to correct as it was apt-get I ran :-)
Do I need to install public keys, don't really have any idea what they
are.
Thanks in advance
Take Care
Winton