Well, if the server.py shows that it got the message it should show up, have you tried to send a SMS to? Shouldnt make a difference but you could try lol, im kinda out of ideas.

You could try change "os.system(command)" on line 63 to something like
To see if it prints debug in console on new call/message, else you could try

To see if it shows a notify to check if its something wrong with my switches lol.

Edit: i just read your PM lol, are you running the server.py in python editor to? the os.system will only work in CMD i think, that could by why growl wont show up.