Also make sure you understand that saving an airport and compiling an airport are not the same thing.
Saving an airport creates an .ad2 project file which contains all the info ADE uses for the airport including lots of data that FS will not need.
Compiling an airport takes all that data and converts it to a format that FS will use and understand. That file needs to be in an active scenery folder.
If I remember correctly, ADE will initially attempt to save the .ad2 project file to My Documents.
WWOD---What Would Opa Do?
Farewell, my freind (sp)