I downloaded Ubuntu 9.04 Jaunty Jackalope ISO and discovered that the file was not downloaded properly. It was corrupt. It failed the md5 check and failed to install inside Sun VirtualBox.
I did not want to download the file again. I have a very poor internet connection. I had downloaded the file from http link with the help of wget.
The ISO was the size as specified in the site. I think this process works only if this holds true. Also, it needs to be available in the torrents. These hold true for the file I was trying to download.