make sure your info (name, address, etc.) you give to PayPal matches the card companies info.. It also could be that its too new.. may want to try again in a week or so. (call the card company to confirm it is indeed activated.)
Im trying to use my new credit card, I got it activated 2 days ago, when I try to use it at Pay Pal to donate I get this message below.
~Your credit or debit card has been declined for this transaction; PayPal could not validate the card. Please verify that the information you entered is correct, or try a different credit or debit card.