http://wordpress.org/support/topic/cant-restore-revisions

There appears to be an issue with restoring revisions. When a user clicks on the revision link, the page redirects to /wp-admin/undefined/.

It looks like this might be tied to the following code: https://github.com/benbalter/WP-Document-Revisions/blob/master/js/wp-document-revisions.dev.js#L60