cannot execute an AE script from Python 2.7

I'm trying to execute an AE script from Python and it doesn't appear that the script argument is passing correctly, or the the script won't run for some reason. I'm using Windows 7 with Python 2.7.

If I use cmd.exe or powershell and try

afterfx -r D:\pipeline\tests\tactic_ae\hello.jsx

I get my "hello world" alert in the AE UI.

However, if I try executing in Python:

subprocess.call(["afterfx","-r","D:\pipeline\tests\tactic_ae\hello.jsx"])

The AE UI takes focus but no alert appears. The really strange part is if I try to do something invalid like remove the -r flag:

subprocess.call(["afterfx","D:\pipeline\tests\tactic_ae\hello.jsx"])

I get an AE error:

After Error Can't import file "hello.jsx": unsupported filetype or extension

It does seem like Python is passing the arguments or the error above wouldn't be generated, but why won't the script run and display the alert? Thanks!