What B7e7US said.
The workaround for payment issues is to put the reservation on hold (free), then call AA, give them the record locator and have the agent process the payment manually. There should not be a fee. Just make sure that - should you have a card that charges currency transaction fees - payment is done in the currency your card is in.
This way, you can also use the AA.com US web site even with a non-US credit card.