Cloud Storage
This error is usually the result of the document being stored remotely on OneDrive, which often acts as backup to both the Documents folder and the Desktop folder.
Even though it shows the document in that folder, it may actually be stored in the cloud and dynamically loaded into Word when needed. This prevents PerfectIt from working properly.
You can solve this by either moving the document to the Downloads folder, or setting the Documents folder to Always Keep On This Device.