"Root element is missing" exit code 500

We are running EasyMorph Command Line Worker v5.3.0.0
We started getting : Root element is missing.
Exit code = 500

What does this mean? What could cause it?

I checked other posts. We are not using ODBC. We are not using the sharepoint connector. We are processing text (CSV) files only.

Thanks in advance.

Try updating your CLW to a more recent version from our website.