I have seen that error and it happened when I saved over a file in an article with a new version. The fix was to delete the article and reimport it.
You can also use the new Relink option in the updated Folio Builder panel to relink the article to its source layouts.
@ Bob L.: I did it the same way like you ... delete and upload the article again.
@ Bob B.: Now I have updated the tools and can use the "relink" article. Thx
My next Problem is:
I choose my folio and open it in the folio producer organizer and in the editor i see only empty frames -> "Layout is missing!"
But I don't understand that the folio acts on my iPad without problems.
i have the exact same problem, but relinking doesnt help. restarting indesign doesnt help. deleting the folio and trying to rebuild everything doesnt help either.
why the hell doesnt he find the file which i apparently have already open?
the whole digital publishing suite is a pain to use so far, sorry
ps: after reboot it worked. wtf?! as this problem frequently happens, this is quite a bad workaround.