Python – PyInstaller error with PyQt when trying to build –onefile

I'm trying to compile a PyQt program using PyInstaller 1.5. Both of the following programs work fine for me when I use –onedir (the default), but this creates rather large programs. I want to use the –onefile option, but when I run the created onefile app, I get the error:

Traceback (most recent call last):
  File "<string>", line 11, in <module>
  File "pyinstaller/PyInstaller/loader/iu.py", line 468, in importHook
raise ImportError("No module named %s" % fqname)
ImportError: No module named PyQt4.QtCore

This error occurs for both this:

import sys 
from PyQt4 import QtCore, QtGui 

app =QtGui.QApplication(sys.argv) 
window =QtGui.QMainWindow() 
window.setCentralWidget(QtGui.QLabel("Hello")) 
window.show() 
sys.exit(app.exec_()) 

and this:

import sys
import PyQt4.QtCore, PyQt4.QtGui 

app = PyQt4.QtGui.QApplication(sys.argv) 
window = PyQt4.QtGui.QMainWindow() 
window.setCentralWidget(PyQt4.QtGui.QLabel("Hello")) 
window.show() 
sys.exit(app.exec_()) 

Does anyone have any ideas?