trying to load ff on new supported tablet, but it only gives me the option of going to ff already loaded on my phone

Whenever I try to load ff on my asus transformer tablet, the download only gives me the option to load it to my phone--that already has ff downloaded. There's a box in the download that lists the devices to send the download to, and the only option it will let me choose is my phone, and it won't let me add the tablet. This tablet is a ff supported device.