YOu do realise IF you just tie your ESTOP button input to the Reset function in mach you will have the same thing. When the Estop button is pushed MACH will go into reset and Flash the message on the ticker0 next to the reset button.
Learning Mach VB is NOT something to be attempted here in the forums. There ARE videos available AND manuals to help you learn the process.
http://www.machsupport.com/videos.phphttp://www.machsupport.com/documentation.phpThen When you need help you can call on us here.
Hope that helps,