Python launcher not working on Mac after Leopard upgrade?

[André]

I just installed Leopard on my Mac.  I already was using Python 2.5.
I can run a Python script from a terminal window by typing "python
script.py" as one would expect ... but not using the Python launcher
either directly or indirectly (by double clicking on a Python icon).
Has anyone else observed this and, more importantly, found a fix for
this problem?

André