OK, something to do with the OS version, I think. I've reproduced the problem on another system running 10.6

I think you'll find that the problems vanish if and when you upgrade your version of OS X. In the meanwhile, thank you for drawing this to my attention, and I'll add a note about the script requiring OS X 10.7 and above.

(I won't advise you to upgrade your Python installation to 2.7, because while it is possible to have two versions of Python installed concurrently, you have to be careful not to replace the version which OS X is using, in case there are any script dependencies in OS X processes. I am also not sure that it is the Python version that is the issue).

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