Hi Andrew,

I started my emacs with the -Q option, and to my surprise I got the same
error that you have described.  I've been able to hunt down the source
of this problem, and it is an old version of org-export-as-org, which
means that you are not loading the latest version of the core org-mode,
but rather the version distributed with Emacs.

This is what happened to me when I started with the -Q option and simple
required org-install without first adding the path to the newer version
of org-mode to my load path.

An easy way to verify that this is the case is to call describe-function
with C-h f org-export-as-org, then jump to the source-code of the
function by pressing enter on the linked function name, and jumping down
to the last 5 lines of the function definition.  If they don't look like