It seems like the "add to cart" button is really picky about the exact spot you click on it. It took a few tries to figure out that you have to get the far left corner. Also, none of the links on the Season 2 page seem to work, including the ones to buy it. I've got the latest version of IE and latest version of flash.
Also, my mom filled out the order info, since it's a Christmas gift for me, and put in her own e-mail address on the order form (while signed in on this account). Probably would have been a better idea to buy the gift one, but too late now. The download links and everything show up in my account, and it activated just fine with my username and password, but I just want to be sure that the different e-mail address won't screw anything up further down the line.