I got same error as Br4ndon got. I'm not familiar with scripts (and English), but I tried to solve this problem.
In Evernote6, "HTML content" no longer contain "<body></body>" (I confirmed this by inserting "return this_html" just above the line containing this problem.). So I replaced "find text "<body.*?>(.*?)</body>" in this_html" with "find text "\".*?(.*?)\"" in this_html", and this change seems working well.
I hope this helps.