I'm having trouble installing Zimbra! I have a computer Ubuntu 10.04 and trying to install the Zimbra Open Source Edition x86.
During the installation process an error appears saying I need to change my hosts file.
I do not quite understand linux, yet managed to open the HOSTS file, but having trouble to edit it!
I have no idea how to edit the hosts file, I do not know how to configure it.

What is the proper way to change my HOSTS file, knowing that my IP is and the computer name is Exchange?

Can anyone help me?