It looks like there's a bad macro expansion on:

http://mms.mongodb.com/help/faq/backup/

Under the question "What MongoDB permissions does the Backup agent require?" it says:

as described in required-permission-mms-backup.

And I think the "required-permission-mms-backup" is supposed to be a link to some other page. See attached screenshot

I only marked it as major because a customer reported it so its definitely in the path of things they're looking for. Hopefully its a quick fix.