Hello everyone. I'm having some trouble with a program I'm writing. The program uses PyQt4 and qt4reactor. When the program is started it requests a file from the server that it downloads and saves onto the client machine. The file is a python module that gets dynamically loaded and used in the program. All of this works fine on a Max OS X 10.4.6 using Python 2.4.4 and Qt-4.1.0. When I try to run the program on window I get this error message: File "C:\path\to\downloaded\module", line X, in init self.panel = PhoneBookPanel(self, parent.getWiget()) exceptions.TypeError: 'NoneType' object is not callable parent: instance of QMainWindow parent.getWidget: return a QWidget that will be the parent widget of self.panel self.panel is a QWidget instance that will be added to parent.getWidget() The thing thats really confusing me is that although it works perfectly on a mac it crashes on windows using the same version of Qt and Python!!