Hi,
 I am trying to write my thesis using org-mode and followed this thread:
http://lists.gnu.org/archive/html/emacs-orgmode/2007-12/msg00034.html.
But instead of putting everything in one file, I was creating one file for
each chapter with the assumption that like LaTeX I should be able to
combine them in one master file.
I am able to export each chapter individually into PDF. I tried to include
them in the master file as this:

#+include "~/Documents/thesis/introduction.org"
#+include "~/Documents/thesis/chapter1.org"
#+include "~/Documents/thesis/chapter2.org"
#+include "~/Documents/thesis/discussion.org"

 but when I tried to export the master file, I get error messages on
figures that I created using tikz package (topbot is a shape I define using
tikz):

----8<------->8-----
Latexmk: Reference `fig:figure1' on page 18 undefined
...
...
! Package pgfkeys Error: I do not know the key '/tikz/topbot' and I am
going to
 ignore it. Perhaps you misspelled it.

----8<------->8-----

I have the same LaTeX headers in each file. I tried moving it to the top of
the master file but that did not help.
Concatenating all the files into one sort-of works but when I replaced
biblatex' \printbibliography[heading=none] at the end of each file with
\newrefsection[biliographyfile] in the combined file, the reference
sections become empty.

Is there a nice way to combine multiple org-files that I am missing?

Thanks,
  Subha