As far as I can see, the application doesn't have a backup method, so if you forgot your password there's no official way to get our files back. However, there are a few alternative options that you could try, but I can't guarantee that any of them will work:
- Run 7-zip file manager (make sure that the option to view hidden files is enabled), go to your locked folder and check the hidden folder inside it.
- Connect your hard disk to a different PC.
- Try installing Linux on a different partition and booting your PC from it, because Linux has ways to see even the locked/hidden files allowing you to get access to your content.
You can try using Slax as it's small and can be launched from a USB drive: https://www.slax.org