Comment 4 for bug 646834

i'm a total newbie, only using ubuntu10 1 cos i dont want to use microsoft anymore:)
i know nothing about using code, nor do i have the indepth knowledge needed to understand the answers on these forums.
i keep getting a warning triangle, and then the message
W:Failed to fetch http://<mirror>/bin/linux/ubuntu/hardy/Release.gpg Something wicked happened resolving '<mirror>:http' (-5 - No address associated with hostname)
when i follow the steps in update manager.

can anyone give me a fix in plain english?

cheers:)