Having recently purchase 'Engineering Mathematics' - 5th Edition, I was disappointed to find that the companion CD contained software that would only work with Windows, and not on my Ubuntu Laptop, or Mac Desktop.
Despite Microsoft having held a seemingly unassailable market share over the past 20 years on the Desktop, current trends show that more and more people are using Mac OSX and Linux on the desktop - with Linux being particularly strong in certain academic fields.
I'd like to suggest that palgrave do not release a 'Mac OSX version', nor an 'Ubuntu version' of the personal tutor; but anticipate the current market trends and put the personal tutor 'in the cloud.' This would enable you to centrally-manage updates and revisions to the tutor, rather than having to 'push' updates to your customers. It would also enable you to leverage the intelligence of the 'community' of 'Engineering Mathematics' readers since its first publication in 1970.
I won't preach toward you about the benefits of choosing "open source software" as your platform (although do take a look at moodle for your Virtual Learning Environment). However, I'd like to place emphasis on the potential of the 'community' that such a website would create. Instead of having students as independent satellites, you'd bring them together online to encourage collaboration and solutions.
These are the skills that the academic community are trying to encourage. It was Tim Berners-Lee, of the academic community, who started the World Wide Web at CERN. Please consider contributing yourselves.