I’m receiving the same error.
I was able to have 1 post be submitted, now every post is providing this error.
I notice that I get this when I remove the title from the submission form.
Once I put the title back, every thing was good.
Sorry for the late reply.
This “Security Check” due to the use of wp_nonce_field function which is a part of a security measure to ensure that the data being sent for submission comes from the WordPress administration pages and not an external source.
@devoslack – you are right. Its implemented for title field. But I will double check the code again to make sure how it can be more usable and if its necessary I might remove it as well in the next version.
At the moment please use title for it to work without any problem.