For security reasons loading local system files was blocked by default in Flash Player 23. There is a work-around. See the section 'Disabling local-with-filesystem access in Flash Player by default' section of the Flash Player 23 release notes.
I don't really understand what I have to do, also the link in the third comment does not exist anymore. Can someone maybe explain what I have to do? I am not the best in understanding computer terms...
Flash Player doesn't really let you run content from the local filesystem anymore. It's problematic from a security perspective. It made sense in the late '90s/early 2000s when CD-ROMs were prevalent, but it's 2018 and the threat landscape is quite different than it was in the early days when that functionality was conceived.
Long story short, we turned that functionality off. It's a bad idea to re-enable it; however, if you edit Flash Player's configuration file, you *can* turn that functionality back on. A better choice would probably be to see if the publisher provides an online version of the examples in the book that you bought.
If that doesn't work, instructions on how to enable this functionality are available in the Flash Player system administrator's guide:
See the EnableInsecureLocalWithFilesytem flag on pp.36. "EnableInsecure" denotes that enabling this flag is usually a bad idea.
See page 29 for instructions on modifying mms.cfg.