If I load a python source file using python-mode.el, and then subsequently
look at a .org file using org-mode.el, I get an error:

Lisp error: (wrong-type-argument stringp nil)

and then I cannot see my .org file (nothing is displayed in the buffer).

Specifically the steps to reproduce are:

1) run 'emacs --no-site-file --no-init-file'
2) eval "(require 'python-mode)" to load python-mode.el
3) find-file "some/python/file.py"
4) find-file "some/org/file.org"

and I get the above error.  If any of the above steps are omitted (ie, if I
load python-mode.el, but don't actually look at a python file), I don't get
the error.  I've included a traceback below.  I'm also submitting this to
as a bug to org-mode (https://bugs.launchpad.net/python-mode/+bug/1108910).
 I've never had problems with org-mode in this vein before, and this
started immediately after starting to use python-mode.el, so I suspect that
the problem lies there.  However, the whole traceback seems to be in
org-mode code, so I'm sending this to you, as well.

I'm running:
OS X 10.7.5
Emacs 24.2.1
org-mode 7.8.11
python-mode 6.1.0

Backtrace attached.

Thanks,
Greg