PayPal, Bank, or me issue?

Hello, Im trying to purchase the Aimware Master Package lifetime which is "£ 159.00" now from what I've read via other forum posts it looks like that Paypal will automaticly convert my native currency (USD) to what Aimware uses (‎GBP). Now my issue originally occurred when I tried to purchase the item without a Paypal account and with my credit card where I was getting an error and after reading and searching I came to the conclusion that it was because that card was already linked to an already existing Paypal account, which it was. So I log in, my Credit Card is there and my bank checking info is also there but I have yet to confirm the bank account, but at the time I didn't see it to be an issue but I guess MIGHT be a reason why my payment isnt going though. So now when I went to buy the master package for the lifetime subscription I get this error: "You cannot use this credit card for this transaction. Please use another funding source.

• You will need to confirm your bank account. Once your bank account has been confirmed, you can continue this payment."
  

My main question is WHY can I not use my card? Is it due to the native currency (USD)? Also SHOULD I even confirm my bank account information because will I even be able to buy the product even after I confirm it or is it just going to error out again? Should I just put the money I need onto a prepaid Visa card and then make a paypal using that card (If I could get the EXACT amount I would need in USD I would appreciate it as well) By the way, the current balance on my Credit Card is over $300 so I dont suspect that to be an issue but who knows.

Thank you and I hope to have this sorted soon because I dont want to have to contact my bank to get my login id and password for it nor do I want to wait "2-3 business days" but if I MUST then I will.