If I had to guess I would say your issue stems from not having an e-mail client setup on your computer. When you click a mailto link it attempts to open up your local e-mail client. From the sounds of things you don't have a local e-mail client therefor you receive error. You could as a workaround copy the email link to a web based e-mail solution such as google. if you would like help setting up a mail client please ask.