wrong type argument char-or-string-p when moving from notmuch 0.5 to 0.6 or 0.7

[David Bremner]

On Sun, 7 Aug 2011 02:27:20 -0700 (PDT), daudi <dw at davidwhiting.me.uk> wrote:

> With notmuch 0.5 installed and emacs 23.2.1 I can search, show and read
> results fine. With notmuch 0.6 or 0.7 in emacs I can search and get a list
> of results, but when I try to view a result I only see the message headers.
> In the messages buffer I get:
> 
> notmuch-show-insert-part-*/*: Wrong type argument: char-or-string-p,
> ((:content-type "text/html" :id 2) (:filename "report_en.pdf" :content-type
> "application/octet-stream" :id 3)) [2 times]

Do you have a public message that you can duplicate this problem with?
Failing that, a backtrace (obtained by M-x toggle-debug-on-error) might
give some clue.

David