Version 2.2.0 has an issue with new links to Dropbox. If you are already linked, you will not see this issue. Using Link to Dropbox will fail in 2.2.0 for new links. Poll Dropbox will also fail in 2.2.0 if changes are detected.
These two issues are fixed in 2.2.1 which should be available by next week. Meanwhile, existing Dropbox Links continue to work fine and Roomie Service Backup/Restore has no such issues.