BUG #10089: apt-get update cannot fine the deb info of postgres

The following bug has been logged on the website:

Bug reference: 10089
Logged by: Hesam
Email address: hesam(at)recyclingcalendars(dot)com
PostgreSQL version: 9.2.4
Operating system: Debian Squeeze Release 6.0.7
Description:

Hello

When I run apt-get update, I get the following message regarding postgres:

----------------------------------------
W: A error occurred during the signature verification. The repository is not
updated and the previous index files will be used. GPG error:
http://apt.postgresql.org squeeze-pgdg Release: The following signatures
were invalid: KEYEXPIRED 1381654177

W: Failed to fetch
http://apt.postgresql.org/pub/repos/apt/dists/squeeze-pgdg/Release

W: Some index files failed to download, they have been ignored, or old ones
used instead.
----------------------------------------

And when I run apt-get upgrade, I am getting this error message:

----------------------------------------
Err http://apt.postgresql.org/pub/repos/apt/ squeeze-pgdg/main
postgresql-client-common all 147.pgdg60+1
404 Not Found [IP: 213.189.17.228 80]
Err http://apt.postgresql.org/pub/repos/apt/ squeeze-pgdg/main
postgresql-common all 147.pgdg60+1
404 Not Found [IP: 213.189.17.228 80]
Failed to fetch
http://apt.postgresql.org/pub/repos/apt/pool/main/p/postgresql-common/postgresql-client-common_147.pgdg60+1_all.deb
404 Not Found [IP: 213.189.17.228 80]
Failed to fetch
http://apt.postgresql.org/pub/repos/apt/pool/main/p/postgresql-common/postgresql-common_147.pgdg60+1_all.deb
404 Not Found [IP: 213.189.17.228 80]
E: Unable to fetch some archives, maybe run apt-get update or try with
--fix-missing?

----------------------------------------

I will be grateful if you let me know how to resolve this issue, as I need
to upgrade the server.

Thanks,
Hesam.