I've fixed this problem with the attached patch.

I'll push this patch up to the repository as soon as repo.or.cz comes
back online (looks like it's been down for the last couple of hours)

with the patch applied the following will now tangle
--8<---------------cut here---------------start------------->8---
#+begin_src emacs-lisp :tangle yes
  (message "is a problem?")
#+end_src
--8<---------------cut here---------------end--------------->8---

Best -- Eric