As noted, I am getting this error recently when packaging files or books. These are 2+ years old (ID4) and were created long before I became a CC subscriber, so no Typekit. Also, we never saw the problem with InDesign CC, it began with the recent 2014 release. I'm thinking it is a bug in ID2014, hoping Adobe can resolve it soon. Meanwhile, I need a workaround desperately.
Also, preflight indicates no missing fonts. They are all very simple documents. But it is worth noting that the problem does not happen on every doc, but it is about 50%. Some of the documents are 1 page, some are 70.
In our case, I package these documents and send them off to staff for updates, not to be printed. Staff are also CC subscribers.
Really need to resolve this, any help is appreciated.