iMovie Export Issue

Error message: "Unable to prepare project for publishing."

The project could not be prepared for publishing because an error occurred. (-2191)

Why am I getting this error? The only thing I did differently is Important my video files and select Move File instead of Copy Files.

The source of the video files are on my iMac G5 AND not a camera.

I'm running macOS High Sierra version 10.13.6

What's wrong? I've already restarted my Mac, dumped over a Gig of Photo files, and deleted some projects!