Rated 4 out of 5 stars
Not giving up hope yet but version 3.3.1 still does not work on my system: no export to PDF (or any of the other formats for that matter except the mbox). Compared to 3.3.0 I can now select a target directory for output but thats it, no output files appear (not anywhere).This user has other reviews of this add-on.
Are you using prefix in filenames? Anyway try 3.3.2 version, available now in my website, it should work.