EDIT:
There is now an update to Danish Airfields X - Tuno available. The update fixes an mesh/terrain elevation issue and a issue with a wrong ICAO code

Installation:

1. Uninstall Danish Airfields X - Tuno by using the uninstaller located in your Windows start menu under "Vidan Design"
2. Log into your Simmarket account and download dax_tuno.exe
3. Install the scenery again

If you purchased Danish Airfields X - Tuno after July 7., 2013, you do not need to go through this process