If you end up with 209 errors in the log then the problem is on your side and not in the SDK. The SDK is far from perfect but me and many others start new scenery projects and export files every day without any big problems. This part is a bit unpolished but it work.
My suggestion is:
Open and load your scenery.
Build the scenery and ensure that you got no errors related to the airport itself.
Open and clear the console.
Now export the file again. What does the console say?
If the console log were fine then save and build the scenery again.
Now open and load the project again.
Look in the objects list, you should now find your test file there.