Here's the first bit of the XRC file provided in the tutorial:
#design layout in a separate XML file
<?xml version="1.0" encoding="utf-8"?>
<resource>
<object class="wxFrame" name="mainFrame">
Trying to load the file as provided doesn't generate any messages or exceptions, but the LoadFrame() method returns None, causing the first call to FindWindowById() to throw an AttributeError.
Changing the first line to an XML comment causes the same thing to happen. I don't know enough XML to decide if that's a bug in the parser, but I suspect that it is.
Placing an XML comment after the first line seems to work, as does deleting the <?xml version="1.0" encoding="utf-8"?> bit altogether.
Here's the link: http://wiki.wxpython.org/XRCTutorial
I'd fix it myself, but the page is locked.