According to the information found on the official website, DeLorme is not a brand owned by Garmin. Their website is still available, but I couldn't find anything related to the availability of Street Atlas. This means support practically doesn't exist anymore. The only thing you can do is to access the built-in Help section to learn how a user can set the home location when the start of the app.
Keep in mind that Street Atlas might not have this option at all, but look through its configuration options.
Additionally, get in touch with developers through the Customer Service link: http://www.garmin.com/en-US/company/contact
