I had the same issue. I asked what pen would work and I was told to go to the Dell site and order one. I ordered the PN557W and apparently there are no drivers for it. So I paid $60 for nothing. so much for using anything Dell from now on. its like a gimmick. get you tell you what you want to hear spend your money and nothing works when you get something you want. I have tried googling what Active Pen would work or compatible and come up with the same one.
This is incredibly frustrating because I spent 30 minutes with Dell Support over chat and they did initially point me to a capacitive pen, and when I asked about the Premium Active pen (PN579X), I was told very clearly that it WOULD work, so I purchased it. Good thing I bought it through Amazon so I can return it !