I am having this problem too, here is what I got...
Notice: Undefined variable: payment_type in /home/XXXXpublic_html/modules/paypal/express_checkout/payment.php on line 289 Notice: Undefined variable: message in /home/XXXX/public_html/modules/paypal/express_checkout/payment.php on line 289 Fatal error: Uncaught exception 'PrestaShopException' with message 'Can't load Order status' in /home/kay/public_html/classes/PaymentModule.php:174 Stack trace: #0 /home/kay/public_html/modules/paypal/paypal.php(1366): PaymentModuleCore->validateOrder(45, 0, 1.5, 'PayPal', NULL, Array, 2, false, '27a92ef75a2a756...', Object(Shop)) #1 /home/kay/public_html/modules/paypal/express_checkout/payment.php(290): PayPal->validateOrder(45, NULL, 1.5, 'PayPal', NULL, Array, 2, false, '27a92ef75a2a756...', Object(Shop)) #2 /home/kay/public_html/modules/paypal/express_checkout/payment.php(306): validateOrder(Object(Customer), Object(Cart), Object(PaypalExpressCheckout)) #3 {main} thrown in /home/kay/public_html/classes/PaymentModule.php on line 174