Can't update

[Jim]

This is happening in Kubuntu-9.04.
Can't update.
I also get a error sbout "some obsolete package versions installed" 
(their lib files), but I can't get updates until I resolve 
'us.archive.ubuntu.com', connection
The network is working fine with eth0 and Ican go to that URL with the 
Konqueror web browser.

 
Download failed.
The list of errors is attached. The recovery for this case is currently 
not implemented. If you see 404 errors, it might be useful to try 
fetching package lists (see the Sources tab) and retrying the operation.

The error was:
APT Error. Context:
    Package download failed,
    
http://us.archive.ubuntu.com/ubuntu/pool/multiverse/f/flashplugin-nonfree/flashplugin-nonfree_10.0.15.3ubuntu2_i386.deb: 
Could not resolve 'us.archive.ubuntu.com',
    
http://us.archive.ubuntu.com/ubuntu/pool/main/a/alsa-plugins/libasound2-plugins_1.0.18-1ubuntu3_i386.deb: 
Could not resolve 'us.archive.ubuntu.com',
    
http://us.archive.ubuntu.com/ubuntu/pool/universe/u/useragentswitcher/useragentswitcher_0.6.11-0ubuntu2_all.deb: 
Could not resolve 'us.archive.ubuntu.com'