Buttons issue

Hi all

I am doing a an application for an ATM for some research purposes. I have completed the flash coding/ animations. I have a problem in one of the screens.

In the application there is a screen for selecting customized amounts for eg. $960.

My problem occurs when I press the back button in the screen. when i press the back button in this screen, it goes to the previous screen, but the buttons in the previous screen are not functional. What will be possibly wrong ?

I have used scene wise programming, there are like 5 different scenes in my app.

awaiting a solution,