The tool references a script that imports or adds a toolbox which is either inaccessible or does not exist.
Solution
Ensure that the Python script is correctly referencing the toolbox and the toolbox is accessible. Some possible reasons the import failed include the following:
- The toolbox does not exist.
- There is a syntax error or typo in the path reference to the toolbox.
More information
Ensure that arcpy.ImportToolbox or arcpy.AddToolbox is used correctly and the toolbox exists.