I have the exact same issue as Eric in regards to payment not working with the same error.
Invalid data string during payment.
However, I am trying to renew my subscription and I do not or want to use Paypal unless I can simply pay as guest. i don't not want to create an account with Paypal for any payments.
Ok - I fixed this on my end however it appears to be an issue with how your system handles CVV values that start with "0" as it get stripped. So if your CVV is "011" the system will translate it as "11" since I would speculate the payment system requires three digits but only submits two digits it throws the error.
I used another credit card that didn't have 0 beginning with the CVV and I was able to make the purchase however, I had to use a personal card and need my business card to work.