The tool is not licensed to be executed. Either the license to run the tool is not available or the license is not active.
To use an extension for which you are registered or licensed, you must enable it in the Extensions dialog box for the application in which you will use it. To open the Extensions dialog box, choose the Extensions command from the Customize menu in ArcMap, ArcCatalog, ArcGlobe, or ArcScene (the application that comes with the ArcGIS 3D Analyst). If running geoprocessing tools from a script, the SetProduct and CheckOutExtension functions may be required to set the appropriate product or license to run the tool. See Access to licensing and extensions for more information.