For those who are unfamiliar with Linux, the application is a great starting point. Once the user gets booted in through the CD or USB, the app walks them through the install process very well.
However, if things go wrong, the application does nothing to keep the user informed. There is a single information line, and double-clicking on that shows a mini-console with some verbosity, but it's going to mean nothing to the layman. Even worse, there's no clear way to get out of a failing install process. This makes a scary situation even scarier.
The app should include some reassuring information for the user about what's going on, and there should be easily locatable documentation to help people who run into trouble.