It's not the find, it's the export. When you set up the Export Records step, the dialog has a spot for selecting fields to be exported. The error message is telling you that you haven't selected any fields for export in that dialog.
I thought that the Export Records step would export everything, unless fields were explicitly selected? I've seen this same syntax in other scripts and answers in the discussions. Even the FileMaker help shows similar syntax:
Go to Layout ["Invoices"]
Perform Find [Restore]
Sort Records [Restore; No dialog]
Export Records [No dialog; "Unpaid Invoice List.xlsx"; Unicode (UTF-16)]
How can I tell Export Records to export all fields from all records? I can't find any documentation on it.
My answer assumes that you are using FileMaker 15. The process is the same with older versions but some of the steps to get to the correct dialog differ.
Open this script in the Scripts Workspace
Click the Gear icon
Click Specify for "Specify Export Order"
Have never heard of leaving that option unspecified and getting all fields.
That was the key, thanks! It's surprising that I haven't seen more documentation on the Specify Export Order function being required. It seems strange that it's a checkbox that can be disabled, given that the function doesn't seem to work at all without it.
You can set it up so that a dialog opens and the fields are specified at the time the script executes. That's not how I'd do it as it expects the user to know what fields are which when selecting fields from various table occurrences, but that's why it's there.