Problem with payment by papyal: At this time, we are unable to process your request

Hi,
I have problem with payment by paypal.
When I try buy someting to see if it is work and I come to paypal to do payment Paypal tell me this:

"At this time, we are unable to process your request. Please return to AclothSale-OEM brand and try another option."

What to do?
Thanks!

Possibly the configuration is wrong. http://www.zen-cart.com/content.php?20

Could it be possible that you are trying to login to pay with the same account that is listed to accept payment?