Traceback (most recent call last):
          File "/home/ed/monkey-3.0/Twisted/twisted/internet/defer.py", line 107, in maybeDeferred
            result = f(*args, **kw)
          File "/home/ed/monkey-3.0/Divmod/Nevow/nevow/rend.py", line 532, in renderHTTP
            return util.maybeDeferred(self.beforeRender,ctx).addCallback(
          File "/home/ed/monkey-3.0/Twisted/twisted/internet/defer.py", line 191, in addCallback
            callbackKeywords=kw)
          File "/home/ed/monkey-3.0/Twisted/twisted/internet/defer.py", line 182, in addCallbacks
            self._runCallbacks()
        --- <exception caught here> ---
          File "/home/ed/monkey-3.0/Twisted/twisted/internet/defer.py", line 317, in _runCallbacks
            self.result = callback(self.result, *args, **kw)
          File "/home/ed/monkey-3.0/Divmod/Nevow/nevow/rend.py", line 533, in <lambda>
            lambda result,ctx: self._renderHTTP(ctx),ctx)
          File "/home/ed/monkey-3.0/Divmod/Nevow/nevow/rend.py", line 566, in _renderHTTP
            doc = self.docFactory.load(ctx, preprocessors)
        exceptions.AttributeError: 'NoneType' object has no attribute 'load'