Thanks for your problem report. It looks as if the folder selection button is not working.
As for the error you are getting, this looks like its is being caused by insufficient rights to the config file. Can you please ensure the file is not read-only and that Windows is not restricting you from writing this file due to permissions?
Just to let you know that the ‘store location’ folder select button has been fixed.
I assume that you resolved your issue with the config file not writing.