Getting Ubuntu 'Hardy Heron' on to a VM - An Unhappy Saga

I've been meaning to dip my toes into the Linux water for a while now - my last exposure being a brief one about ten years ago at Uni. Yesterday evening I thought I'd actually do it. My particular motivation in this case was to run Oracle, something I'm working with a lot at work, and I figured I might as well run it on Linux as not (although we run it on Windows at work). So, with my Ubuntu