First of all ensure you have the latest version of the Aircraft Converter installed. It might be necessary to remove the previous version first, before installing the latest version.
Then also delete the complete folder 'Aerofly FS 2 Aircraft Converter' in the Documents folder of Windows.
After that right click on the folder dr400 of the SDK and try to convert the airplane again.
No manual editing of any config files should be required.
This works; now have the dr400 ready to use. Thanks!