You may want to re-test with Popen(..., close_fds=True) with the latest
Python 2.6. From the latest docs:

http://docs.python.org/library/subprocess.html

"If close_fds is true, all file descriptors except 0, 1 and 2 will be
closed before the child process is executed. (Unix only). Or, on
Windows, if close_fds is true then no handles will be inherited by the
child process. Note that on Windows, you cannot set close_fds to true
and also redirect the standard handles by setting stdin, stdout or stderr."

In Python 2.5, you can't use close_fds on Windows. In the 2.5
documentation (ActivePython 2.5.2.2) the above paragraph ends with
"(Unix only)."