I've never had this problem on National's website before. When logged into my account or my wife's account, I am trying to rent out of BOS. I cannot advance past the car selection page. I get system error. I tried to make a reservation out of FLL (last airport I rented out of), and was able to advance past the car selection page. Also, while logged out, I was able to make a reservation out of BOS. I called and made a reservation over the phone. Now, I cannot access that reservation.