Thank you for your post! This error suggests that MAPublisher was installed under different permissions, and you do not have access to write the license file to the default location (C/ProgramData/Avenza/MAPublisher10). To remedy this, please close Illustrator and MAPublisher, and then right-click on Illustrator and choose More > Run as Admin. When Illustrator opens, please go to the MAPublisher License Management dialog, and click “Retrieve” to get your license. Once the license is written in the correct location, you will no longer need to run the software as admin but can open it normally.
Please let me know if this helps resolve your problem! If you are still having problems please reach out to our Support Team directly via support.avenza.com and we’d be happy to help!