IronPython and PyFit -- revisited

In my earlier post, I omitted one crucial detail, which I hadn't actually connected with getting the PyFit system to work, and that is I had already added the existing Python 2.5 standard libraries to my IronPython 1.0.1 site.py file thus:--

This should not be needed if you use FePy instead; and may not be needed for 1.1 or 2.0