Hum, I didn't realize os.chmod() worked this differently on Windows. Seems like I bumped into bug #755617 (os module: Need a better description of "mode"). Per that bug, I googled for '_chmod msdn' and came up with the attached patch. However, I don't have a Windows machine handy to test. Could someone with a Windows machine try the patch?
I'll try it, but there were no attachments. Distinctions among "user", "group" and "world" are unique to Unix. Windows has a much more elaborate permission scheme than that, but at chmod()'s feeble level it's essentially just "nobody can delete me" or "anyone can delete me".