Unfortunately, Alfred has closed the forums and I don't think he monitors them at all. I see the same issue but it does seem to be possible to manually enter the location and save it. I actually run my the renamer in a Windows 8 VM that I haven't bothered trying to upgrade yet (I also run Vuze and VPN software in it...).
I suggest trying to enter the location manually. You can always navigate to it in Explorer, click in the address bar (after all of the text, so that it gives you the "c:\folder\subfolder" format) and cut and paste that into therenamer. Make sure you click save!
I hope this helps.
You can try contacting Alfred at firstname.lastname@example.org
, Twitter: https://twitter.com/theRenamer
, Facebook: https://www.facebook.com/theRenamer
But I think he may have moved away from the project for the most part.
Another thing you can absolutely try is right-clicking on the 'theRenamer' icon and choosing "Troubleshoot compatibility". Choose "Try recommended settings" which will run it with Windows 7 compatibility settings. This does seem to permit you to change the locations using the normal method; however, there is a warning on the main download page not to do this! I think this may have more to do with running it on a non-windows PC or something? It may prevent the program from working properly so do it with the understanding that you might have see strange behavior, should be an easy fix though!