Problem with flashwin.py reading variables from AS3

I'm using the flashwin class of wxPython to display Flash content, and
for the most part it works beautifully. However, with Flash content
that uses ActionScript 3, I'm having getting my Flash script to read
variables from the SWF. It works fine if the SWF is compiled using
ActionScript 2 though.

I put together a stripped down complete example that contains a simple
Python script and the AS2 and AS3 SWFs, if anyone is interested in
testing:

http://sinkingsensation.com/dropbox/as3test.zip

I'm reading the variables from my wxPython script like this:

self.flash.GetVariable('myTestVar')

This works perfectly with SWFs that use ActionScript 2. However, when
used with ActionScript 3 SWFs, I get the following error:

(-2147467259, 'Unspecified error', (None, None, None, 0, None))

I've tried setting that variable in Flash a number of different ways,
including:

MovieClip(root).myTestVar = "test1";
var myTestVar = "test2";

Neither seem to work.

Can anyone think of anything I can do to fix?

Or some workaround that will allow one-way communication, from the SWF
to the Python script?