Hi Auds, and welcome.
arloG is right.
It is very likely that the shield is using some pins that the original sketch is depending on.
That's why you always need to check compatibility of shields.
In this case a fix might be relative easy.
But first you should tell more about what shield you are using.
Is it a LCD Keypad Shield (you didn't state that) ?
Because in that case you will have this problem.
Picking an other analog input will not do if you plan on using the keys of that shield.
Also, before replying, read and follow this (click!).
You'll learn how to use the forum correctly, as you seem not to have that under control yet.