FYI: the problem described below is worse with:

    Org-mode version 7.7 (release_7.7.298.gbf3e9)

-- Mike




>________________________________
>From: Michael Hannon <jm_hannon@yahoo.com>
>To: Org-Mode List <emacs-orgmode@gnu.org>
>Sent: Friday, September 16, 2011 10:50 AM
>Subject: [O] Problems with Org-Mode export
>
>
>Greetings.  I've been having problems lately in exporting Org-Mode source-code
>documents to HTML and/or PDF.
>
>I'm running Org-Mode 7.7 with Emacs 23 on 64-bit linux (Fedora 15).
>
>I've appended a document that exhibits at least some of the problem.  The
>problems are similar to the problem described at:
>
>    http://comments.gmane.org/gmane.emacs.orgmode/45316
>
>and can *sometimes* be circumvented by executing org-reload.
>
>In the particular example shown below, the HTML export works as expected, but
>the PDF export fails with message:
>
>    org-export-latex-preprocess: Wrong type argument: stringp, nil
>
>By the way, everything worked fine in the example until I added the last
>source block:
>
>    #+begin_src
 R
>
>      x
>
>    #+end_src
>
>I tried using what I take to be the latest version of Org-Mode:
>
>    Org-mode version 7.7 (release_7.7.290.g65d05)
>
>but that only made things worse.  I tried an HTML export with this version, and
>it generated a horrendous-looking message that begins with:
>
>org-babel-R-evaluate: Wrong number of arguments: #[(session body result-type
>result-params column-names-p row-names-p) Æ=}...
>
>followed by a bunch of stuff containing enough non-printing characters that
>it's hard to reproduce in email, and ending with:
>
>...org-mode/lisp/ob-R.elc" . 9734)], 5
>
>I'd welcome any help/advice that anybody can provide.
>
>Thanks,
>
>-- Mike
>
>########## Sample file that exhibits some export problems
>
>#+TITLE: This is a test
>
>#+AUTHOR: Michael Hannon
>#+email: jm_hannon@yahoo.com
>
>#+BABEL:
 :session *R* :cache yes :results output graphics :exports both :tangle yes
>
>* Getting Started
>
>** Batch Mode
>
>
>#+begin_src R :exports code
>
>pdf("xh.pdf") # set graphical output file
>hist(rnorm(100)) # generate 100 N(0,1) variates and plot their histogram
>dev.off() # close the graphical output file
>
>#+end_src
>
>If we put the code above in a file called =z.R=, we can execute the
>code from the command line via: =R CMD BATCH z.R=
>
>
>#+begin_src R
>  
>  x <- c(1, 3, 5)
>  
>#+end_src
>
>#+begin_src R
>
>  x[3]
>
>#+end_src
>
>#+begin_src R
>
>  q <- c(x,x,8)
>
>#+end_src
>
>#+begin_src R
>
>  x
>
>#+end_src
>
>
>
>