What version of Premiere? Current version 220.127.116.11 it is just plug and play.
Premiere pro CS 6 version 6.0.5
Maybe they are bad drivers for graphics card
Funny that you rate your question as the correct answer.
The answer is that you need to rename or delete the file 'cuda_supported_cards.txt' or add the card to that file.
Thank you cc_merchant for your help and confirmation.
Did you resolve this?
I have the same graphics card, the Quadro K4200, and i'm not sure if it works fine, because I don't feel a significantly boost after install it.
In Premiere CC 2015 the text file "cuda_suported_cards.txt" doesn't exist.