signature & certificate hell

Adobe Reader XI sign and fill grayed out (Sign and Send PDFs)

^This sounds exactly like the problem I am having.  However, a colleague of mine completed and the same exact form and I'm using his answers as a guide.  So I believe that I am completing all the necessary fields in order to enable the signature field.  However, when I click on the signature field it just flashes the blue highlighted color and does nothing.  I have a currently valid certificate load from my CAC card.  I know this because I signed another document yesterday.  Please help.  Technology shouldn't be this hard.