Unable to process payment. Please contact the merchant as the shipping address provided by the merchant is invalid, and the merchant has requested that your order must be shipped to that address.

无法处理付款。请联系商家送货地址为商家提供的是无效的，而商家已要求您的订单，必须运到该地址。

需要把下面这个参数改成0就可以了
如果你使用的是Web Payment Standard的话你找到app/code/core/Mage/Paypal/Model/api/Standard.php，里面有’address_override’ => 1,这一行改成’address_override’  => 0，就可以了

如果你使用ExpressCheckout的话app/code/core/Mage/Paypal/Model/Api/Npv.php,里面有 ‘ADDROVERRIDE’      => 1这一行也改成’ADDROVERRIDE’     => 0，就可以了