If you encounter the following error message when attempting to edit a video in Presenter '13, it indicates the original *.ppta file for your presentation is missing.
"Could not find the video file - <file path>"
Videos and other presentation resources are stored in the *.ppta file that corresponds to your PowerPoint file. Without the *ppta file, Presenter won't work properly.
If this presentation was transferred from another computer, you may need to check its previous location for the original *.ppta file. When you find it, place it in the same folder as your PowerPoint file, and make sure both files have the same name.