[vtkusers] python import error

[doug.blanding at kodak.com]

I have just installed vtk from the cdrom that comes with the VTK UG book
My machine is linux RH9.
I have Python 2.2.2 installed in /usr/lib.
I selected python wrappers during compilation.
After installation, I set the PYTHONPATH variable to the 
VTK/Wrapping/Python directory in my build directory
I then tried to run the first example Cone.py, but got the following 
error:

[doug at maven Python]$ python Cone.py
Traceback (most recent call last):
  File "Cone.py", line 13, in ?
    import vtk
  File "/dnld/vtk-cdrom/vtk-src-unix/Wrapping/Python/vtk/__init__.py",
line 7,in ?
    from common import *
  File "/dnld/vtk-cdrom/vtk-src-unix/Wrapping/Python/vtk/common.py",
line 7, in ?
    from libvtkCommonPython import *
ImportError: No module named libvtkCommonPython

Can anyone advise me on the cause of this problem and how to get around 
it.