I have been looking over some unanswered questions in the Community and came across this post. If this issue is still occurring, I might have a solution - are you on Tableau Desktop 8.3.4 or an earlier version? If so, upgrading to 8.3.5 or a newer version has helped other folks who are encountering this error message. You can check out Upgrading Tableau Desktop for more information on upgrading.
I've actually just come across this issue myself with version 2018.2
For whatever reason repulling the extract allowed it to be published without this issue. (Note that the csv datasource I had underlying the extract was located at a different file path, as I was working on a different machine.)