[Q] "Script Failed" when using Backup add-on with Dropbox topic

I"m attempting to use the Backup program add-on to automatically back up my Kodi installation to my Dropbox account, but keep getting "Script failed" error messages. I've followed Rob Weber's instructions on GitHub, I created a Dropbox "app key" and "secret" and input that into Backup's settings. I've accessed my log files to get the authorization code for Dropbox, and after going to the generated URL, Dropbox tells me "Success!" that I've connected my backup file to Dropbox. But when I go into the Backup add-on and try and do a backup, I get a "Script Failed" message. When the scheduled time comes to do a backup, again, I just get a "Script Failed" message.

Has anyone got the Backup add-on working successfully these days? Any advice on where I might be going wrong?