Python error when setting up access for my App to Dropbox account

You're not supposed to use your generated access token there. As the app says, you should go to the URL it gives you and authorize the app. You'll then receive an access code (not access token) that you need to copy/paste back into the app.

BTW, I've redacted your access token, but you should probably unlink your app (from dropbox.com/account/security) now that your access token has been published here. With an access token, someone can read and write files in your account, so you never want to share an access token with anyone.