Simple QGraphicsScene program
This complete script works for me with PyQt on Windows, displays a small window and waits for me to close it.

from PyQt4 import QtGui

app = QtGui.QApplication([])

scene = QtGui.QGraphicsScene()
scene.addText("Hello, world!")
view = QtGui.QGraphicsView(scene)
view.show()

app.exec_()


A QApplication object must be created before any other GUI objects.