Membership Premium Not working

Membership Premium is not working on my site at all. The subscription form does not work. If its the original form it does not display and if the pop up form, it goes to a white page with a 0. i have uninstalled and removed the tables and plugin from the site and replaced them with the newest version and nothing is working. I have tried it with several themes from different developers and nothing. Some help would really be appreciated. Also the gateway does not seem to be working. I am running wordpress 3.4.1 and membership premium 3.1.2