Hi. My name is Eduardo and i´m from Spain. First of all I wanna thanks Shea and all the people who makes PiMame.
Recently i build a 3/4 scale Donkey Kong Cabinet whit a RPi and a 14" TV. You can see the entire process of the construction (in spanish) here: http://www.retrovicio.org/foro/showthread.php?27582-Donkey-Kong-quot-reducida-quot-con-Raspberry-Pi.
The cabinet start up in Donkey Kong game, but I want to be able to access to other mame games, so i put a button in the back of the cabinet. The idea is that when yo push this button, the cabinet exit from Donkey kong game and enter in advmenu (i don't like mame4all front-end, because it only show names, no snaps).
Well, and this is is my problem: I modified the shutdown script in python found here: http://pimame.org/forum/discussion/564/shutdown-button-using-gpio-pin/p1
for this purpose. The script now is:

import RPi.GPIO as GPIO
import time
import os
GPIO.setmode(GPIO.BCM)
GPIO.setup(17, GPIO.IN,pull_up_down=GPIO.PUD_UP)
while True:
if(GPIO.input(17) == False):
os.system("killall advmame")
os.system("cd /home/pi/.advance")
os.system("advmenu")
break
time.sleep(1)

The problem is that advmenu don't start at all. If i replace advmenu for mame4all, i have no problems, but launch advmenu seems imposible.
Please need help to finish this project. Thank you and sorry for my poor english.