If you have Dropbox links inside your binders, they are probably broken. Dropbox has done this for security purposes. Please see their blog post for more details. If you have issues with this change, you may want to comment on their blog post as many of their customers have already done.
This also broke our connector to Dropbox, so that if you try to create new links to pdfs in your Dropbox, the documents will show up as downloads inside the binder instead of full pdfs that you can view in the binder.
The best alternative for now is to upload these files directly to LiveBinders so that they show up properly inside the binder. If this problem is affecting you and you are close to your file size limit on LiveBinders, please contact us as firstname.lastname@example.org
We will probably have a follow-up blog post on this in the next few days so stay tuned.