This seems to be related to problems at googles end with perhaps
the api not being correctly implemented to start with. Particularly the
docID was incorrect.
I think google worked around the problem with a redirect which the curl
download_file downloaded rather than followed the redirect.
Google have now allowed documents to be downloaded via their API
(http://googledataapis.blogspot.com/2009/02/start-downloads.html) so
the google docs repo plugin could be finished.
At the moment i've set the export format hardcoded, hopefully we can allow the
repo api let the user choose later...
Dan Poltawski