Running an Automator workflow on a server

I created an Automator app/task a couple of years ago to assist with managing my music library. I can either drag and drop files to the app or open in Automator and add files. The task runs, taking the dropped or added files, flattening the directory and moving the empty folders to the trash.

Basically I use a straight By Artist file system.

I now have a NAS which it seems the task can't function on. I get a "No references were given for the move finder items action" error.

The task/app functions fine on items stored in my Mac and on attached external hard drives, just not on the server.

Is there something I need to change to facilitate this?

Also, the workflow runs extremely slow. Is there a way too speed it up a bit?

I use the same app/workflow on an iMac running Hight Sierra and MacBook Pro running Mojave.

Thanks J