System Error when running PyQt4's loadUi()

[Amelie Lesser]

Hello,
I'm pretty new to Qt, Python and their combinations. I'm currently writing a QGIS plugin in python (I used QtCreator 2.1 (Qt Designer 4.7) to generate a .ui-file and am now trying to use it for a Quantum GIS plugin that's written in Python 2.5 (and running in the Quantum GIS Python 2.5 console)).
I am running into trouble when loading the ui-file dynamically when the program runs the loadUi() function. What throws me off is that the error occurs outside my script. Does that mean, I'm passing something wrong into it? Where does the error come in? Any hints on what could be wrong?

# Set up the user interface from Designer
code_dir = os.path.dirname(os.path.abspath(__file__))
self.ui = loadUi(os.path.join(code_dir, "Ui_myfile.ui"), self)

Traceback (most recent call last):
File "C:/Dokumente und Einstellungen/name.name/.qgis/python/plugins\myfile\ myfile_plugin.p y", line 57, in run
self.dialog = myfileUI(self.i face)
File "C:/Dokumente und Einstellungen/name.name/.qgis/python/plugins\myfile\ myfile_gui.py", line 42, in __init__
self.ui = loadUi(os.path. join(code_dir, "Ui_myfile.ui") , self)
File "C:\PROGRA~1\QU ANTU~1\apps\Pyt hon25\lib\site-packages\PyQt4\ uic\__init__.py ", line 112, in loadUi
return DynamicUILoader ().loadUi(uifil e, baseinstance)
File "C:\PROGRA~1\QU ANTU~1\apps\Pyt hon25\lib\site-packages\PyQt4\ uic\Loader\load er.py", line 21, in loadUi
return self.parse(file name)
File "C:\PROGRA~1\QU ANTU~1\apps\Pyt hon25\lib\site-packages\PyQt4\ uic\uiparser.py ", line 768, in parse
actor(elem)
File "C:\PROGRA~1\QU ANTU~1\apps\Pyt hon25\lib\site-packages\PyQt4\ uic\uiparser.py ", line 616, in createUserInter face
self.traverseWi dgetTree(elem)
File "C:\PROGRA~1\QU ANTU~1\apps\Pyt hon25\lib\site-packages\PyQt4\ uic\uiparser.py ", line 594, in traverseWidgetT ree
handler(self, child)
File "C:\PROGRA~1\QU ANTU~1\apps\Pyt hon25\lib\site-packages\PyQt4\ uic\uiparser.py ", line 233, in createWidget
topwidget.setCe ntralWidget(wid get)
SystemError: error return without exception set

[dwblas]

I don't use QT much myself, but would guess that loadUi takes only one parameter, where you are passing two, a file name and "self".
self.ui = loadUi(os.path. join(code_dir, "Ui_myfile.ui") , self)