The only thing that I think would be helpful from an email would be a copy of your Photo Mechanic log file, which you can get by going to Help -> Reveal Support Data. Send that to support@camerabits.com
The reason I suggest a phone call is because we can then jump into a screen sharing session so I can investigate this issue and get a first hand look at what is not working, which tends to be a better approach to mystery behavior than going back and forth through email/forums.
If you set up a new catalog as a test, add a single, small folder, move it (outside of Photo Mechanic), and then try to tell the catalog where the folder has moved to using the steps above, does that work as I have described?