Error: Task <TASKNAME> is not found for instance <TASKINSTANCE name>.
In the XML file, you specified a TASKNAME attribute in a TASKINSTANCE element that references a non-existent reusable TASK element.
Edit the XML file, and verify the TASKNAME and REUSABLE attributes in TASKINSTANCE element the refer to only one TASK element. Include reusable tasks under the FOLDER element, and include non-reusable tasks under the WORFKLOW element. Or, export the object again and then import it.