Few people have informed us that they can't purchase premium membership via paypal using debit/credit card. I don't think there should be any porblem un using debit/credit card as long as you have entered correct details. Most of the members have used debit/credit card via paypal to purchase premium membership. 

There are only two possible scenarios

(1) You are not entering correct details.

(2) Your card is not allowed for International payment. In this call bank and request them to allow using card for international payments.