Log entry for Dropbox issue:
Unknown: errno:2048 Only variables should be passed by reference ./wp-content/plugins/snapshot/lib/destinations/dropbox/includes/PEAR_Includes/HTTP/OAuth/Signature/Common.php on line 58
Also when selecting how to backup database and I select "All Tables" that's what I expected. Instead the backup only contained Wordpress core tables. If that's by design then this plugin is all that useful.