I've got the same problem as noted by Cinematic6436, above. The difference is, I'm running Windows 11. A fresh install of Win 11 was done on a new machine in May of 2022. files2folder ran fine until about April or May of 2023, then suddenly stopped working. I assumed a Windows Update killed it. I re-installed, several times, nothing seems to help. I tried the Registry action listed above. Only found TWO instances of files2folder in the Registry, but I deleted them both. End result? Still have the same problem, with the same error message. BUT, I did manage to kill ALL internet access in the process! I've done MANY Registry edits in the past without problems, but who knows...Windows is a strange, unforgiving beast. Anyway, a Restore from a Back-Up-Point solved the problem.
So, any chance the author could "fine-tune" the program to make it work like it used to? I'd gladly donate, if it can be made to work again....