I can't say I've seen that specific error (and I'm in the middle of a bunch of DA development at the moment). If you see this from the outset (i.e. before it even displays any content) the I would double-check that your Index has been generated, contains content (check the lesson.js file in the File System), and has been published.
If you get this error when trying to display content from the DA panel, check that the content you are trying to display has been published. Due to some particularly Germanic logic, the Index will include ALL content under the DA object, regardless of whether this is published or not - and will therefore be listed in the content panel - but then when a Learner tries to display it, they aren't authorized to display draft content so an error is generated (not the one you show above, but it may be related).
If all of that is good, I would do some troubleshooting:
Failing that, wait until May, when the entire thing is going to be re-vamped (again), anyway! 😉