I experienced that before..all you need just to edit some files.
Try check Patch.dat under
- [your drive]\nDoors\Atlantica\PatchInfo
- Open Patch.dat using notepad or any text editor, make sure it looks like this
path=[path to your AO folder]
Next, delete every files inside Config folder
- [your drive]\nDoors\Atlantica\Config
Then launch the launcher again, and remember to reconfigure your Settings again.
Should able can launch your AO now.