The simple answer to this error is I was using a CD-R disc instead of a DVD-R disc. I got stuck for almost 30 minutes googling around and trying out all kinds of suggestions. Then after downloading ISO image and trying to burn it to the disc using ImgBurn, I got an error message in human language telling me the disc has incorrect format. Could be better, but I got the hint. Developers, we need error messages that a human being of average intelligence can understand.