This option sets the path to the XML file wich contains the style definitions.
By default the editor loads the "fckstyles.xml" file, placed in the editor installation directory. You may point it to another file located outside the editor folder, making it easier to maintain editor upgrades. For example, you may have a directory named "fckeditor_assets" containing all your custom files, while the editor is installed in the "fckeditor" folder. In this case, just set StylesXmlPath as follows:
FCKConfig.StylesXmlPath = '/fckeditor_assets/fckstyles.xml' ;