-ExecStart=/opt/kivitendo/scripts/task_server.pl start
-ExecStop=/opt/kivitendo/scripts/task_server.pl stop
+# Change the user to the one your web server runs as.
+User=www-data
+# Change these two to point to the kivitendo "task_server.pl" location.
+ExecStart=/var/www/kivitendo-erp/scripts/task_server.pl start
+ExecStop=/var/www/kivitendo-erp/scripts/task_server.pl stop