CloudPull 1.5.6 is now available through this web site and through the CloudPull in-app Software Update mechanism. This update will also be available through the Mac App Store as soon as possible.
CloudPull 1.5.6 accepts and follows HTTP redirects from Google when retrieving lists of items. The Google Calendar API has begun occasionally issuing redirects when retrieving a list of calendars. If you have recently seen calendar backup errors, this update should address the cause of those errors.
Update January 31, 2012: The CloudPull 1.5.6 update is now available in the Mac App Store.