Guild wars official store [error]

Hi, i have been trying for awhile to buy additional character slots from the official store but i keep getting an error towards the end.

Payment processing failed at the merchant provider account.
Error=1751052

I'm sure the credit card im using is valid because i have been buying stuffs elsewhere online just recently as well as details filled in properly. Is it because the store is not set up for some regions yet? or?

Thx in advance.

Your credit card company is proberbly denying charges from PlayNC. Give them a call and find out.