You will need to be connected to the internet when you enter the info so that it can be checked by PayPal to confirm that it is correct. If you are connected to the internet and get this error then it may be due to some security software that you have in place. Please check to see if you can disable this temporarily while you test. Please post back and let us know what the result is either way, if this needs to be looked into further I will ensure that a ticket is opened up for you.