A more specific query ...

[Gib Bogle]

The PyQt4 problem results from having copies of the Qt DLLs in directories that 
are in the PATH, as Doug Bell discovered.  In my case I have two programs that 
use Qt, AMD CodeAnalyst and Matlab.  If I rename BOTH these directories I can 
import the PyQt4 modules.

Since this behaviour did not occur with Python 2.5 and the previous PyQt I was 
using (4.5, I think), it seems that something has changed either with Python 2.6 
or with PyQt 4.7.

It would be very nice to learn how to fix this without renaming directories, 
since I use Matlab frequently.

Gib