koma letter export

[Vikas Rawal <vikaslists@agrarianresearch.org>]

[-- Attachment #1: Type: text/plain, Size: 465 bytes --]

I am trying to use ox-koma-letter for my correspondence. I have a
functioning test file that produces a nice pdf. But I would like to
set it up so as to have one letter per headline, and do subtree export
to produce the pdf. 

I am attaching the test file for the purpose. When I export it using
C-c @ C-c C-e k o, this file gives me the following error:

let*: Wrong type argument: char-or-string-p, nil

Have I made a mistake or is there a bug somewhere?

Vikas


[-- Attachment #2: correspondence.org --]
[-- Type: text/plain, Size: 835 bytes --]


* A Simple letter
:PROPERTIES:
:EXPORT_LATEX_CLASS: vikasletter
:EXPORT_LCO: DefaultAddress
:EXPORT_AUTHOR: Vikas Rawal
:EXPORT_DATE: April 22, 2013
:EXPORT_EMAIL: vikasrawal@gmail.com
:EXPORT_TO_ADDRESS: John Doe\\
:EXPORT_TO_ADDRESS: Other Street 1\\
:EXPORT_TO_ADDRESS: 54321 Other City
:EXPORT_OPENING: Dear ,
:EXPORT_CLOSING: Yours sincerely,
:EXPORT_OPTIONS: backaddress:nil
:END:

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do
eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enimad
minim veniam, quis nostrud exercitation ullamco laboris nisi ut
aliquip ex ea commodo consequat. Duis aute irure dolor in
reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla
pariatur. Excepteur sint occaecat cupidatat non proident, sunt in
culpa qui officia deserunt mollit anim id est laborum.