I'm getting this error when trying to export a file to EPUB3 with Layout:
"HTML Pagination Error. Cannot find a master page with a primary text frame for use as an expansion page".
Don't choose EPUB3 with Layout when doing EPUB export. It doesn't exist.
It is removed in the upcoming InDesign CC because it was a proposed standard Adobe hoped would be approved by the EPUB standards group but has not been released.
What about this tutorial that already 15.000+ people viewed?