Sometimes we hear of cases where the user's financial institution (like their bank or credit card provider) actually blocks the transaction from going through completely. That may explain the error you are seeing.
This is done to protect you from fraud. If this is the case, you should see the charge reimbursed on your credit card within a few business days, or possibly much sooner.
If the charge is not reversed, you should contact your credit card company. Also, you may want to contact them anyway, to let them know this was really you trying to make a legitimate purchase.