From which geographical location are you trying to purchase the subscription?
If you could include the URL of the adobe store you are using, that would be great
We are located in Belgium.
We don't directly go to the Adobe.com site because there we can't really find the FormsCentral product. So we start from the actual formscentral dashboard where there's a link called 'upgrade your account'. From there we are taken to this page:
And when clicking on one of the prices I am redirected to this page:
I included a screenshot of the actual result.
Hope this helps ...
Try clearing your browser cache and cookies. Tha tusually fixes the problem. You could also try another browser.