Calculations with derived fields – is this possible?

I used a derived field on a screen (I used the derived field for a calculation).  When the screen is called, I get a message saying the field cannot be found along with a Safe Call Exception.  I am hoping that I just fudged something up along the way and that this is still possible??

I created the derived field using the Derived Field Wizard.  However, I did notice that a previous post regarding “How to add a Derived Field to Meta Data” can no longer be found.  Therefore, I am wondering if it is still possible to use a derived field and is it possible to add that derived field to a screen?

Any assistance is greatly appreciated!