1. Do you have a folder named fckeditor located in /editors? If not your fckeditor files were either uploaded to the wrong place or are incomplete.

2. Some administrators prefer to rename the admin folder to a unique name to increase security. If you have renamed your admin folder, then you need to be sure to upload the files in the admin folder of the fckeditor download to this renamed folder. (It's better practice to rename the fckeditor admin folder to match your admin folder on the webserver before uploading to the server.)

3. Have you cleared your browser's cache?