The error message that displays when you try to configure FCK editor but you haven't put the actual editor there (just the module) is as follows:
The FCKeditor component is not installed correctly. Please go to the FCKeditor homepage to download the latest version. After that you must extract the files to sites/all/modules/fckeditor/fckeditor/fckeditor/ and make sure that the directory sites/all/modules/fckeditor/fckeditor/editor and the file sites/all/modules/fckeditor/fckeditor/fckeditor.js exist. Refer to the readme.txt for more information.
The destination to extract the files to is incorrect - it currently reads sites/all/modules/fckeditor/fckeditor/fckeditor/ whereas there should be one less "/fckeditor" - it should be sites/all/modules/fckeditor/fckeditor/ - I believe this is extremely important since many users will run into this problem.