your is a DragScript … in “On End” tab you can start only normal programming script or executable.
DragScript is not a script is an Engine of Voyager that allow you to run sequentially and with some logic a set of action block to create your simple or complex set of task. So no programming language.
If you want to use DragScript you must to do exactly the opposite : add in your DragScript the sequence block at beginning and configure it. So when the sequence will be finished DragScript will pass to the next block in the list and execute your shutdown operations.
I remember to you that in the license there is support to remote get help for create your DragScript.
DragScript in the wiki:
Section for DragScript in this forum:
All the best