I am using Ubuntu 10.4.04 LTS with in VMware5.
I used automatic proxy configuration and I'm able to use internet from firefox.
When I wanted to update apt-get update, I am getting following errors.
The following link gives some solution, but I don't have any port number as I'm using automatic proxy
https://answers.launchpad.net/uck/+question/108860.

Error:

Ign http security.ubuntu.com lucid-security multiverse Packages              

Ign http security.ubuntu.com lucid-security multiverse Sources               

Ign http security.ubuntu.com lucid-security main Packages                                  

Err http security.ubuntu.com lucid-security main Packages                    

  Something wicked happened resolving 'security.ubuntu.com:http' (-5 - No address associated with hostname)

Err http security.ubuntu.com lucid-security/restricted Packages              

  Something wicked happened resolving 'security.ubuntu.com:http' (-5 - No address associated with hostname)

Err http security.ubuntu.com lucid-security/main Sources                     

  Something wicked happened resolving 'security.ubuntu.com:http' (-5 - No address associated with hostname)

Err http security.ubuntu.com lucid-security/restricted Sources               

  Something wicked happened resolving 'security.ubuntu.com:http' (-5 - No address associated with hostname)

Err http security.ubuntu.com lucid-security/universe Packages

  Something wicked happened resolving 'security.ubuntu.com:http' (-5 - No address associated with hostname)

W: Failed to fetch http security.ubuntu.com/ubuntu/dists/lucid-security/Release.gpg  Something wicked happened resolving 'security.ubuntu.com:http' (-5 - No address associated with hostname)



W: Failed to fetch http security.ubuntu.com/ubuntu/dists/lucid-security/main/i18n/Translation-en_US.bz2  Something wicked happened resolving 'security.ubuntu.com:http' (-5 - No address associated with hostname)



W: Failed to fetch http security.ubuntu.com/ubuntu/dists/lucid-security/restricted/i18n/Translation-en_US.bz2  Something wicked happened resolving 'security.ubuntu.com:http' (-5 - No address associated with hostname)

Thank you for your response!