Membership Problem

Hey all,
I've recently begun developing a site which I plan to have membership levels offered. Initially, I discovered no problems when I began development with WP 3.0.

However, after installing WP 3.1 and updating the majority of the plug-ins, I have found that the Drag and Drop feature of the Membership Plugin is no longer working in any of my Browsers (Tested: Google Chrome 9.0.597.107, IE 8, Firefox 3.6.15, Safari 5.0.3).

Having searched through the Support Forum, I decided to try the following:
1) Disable all of the plug-ins Except for the Membership Plug-in
2) (Automatic) Re-install WP 3.1 (both with and without the Plugins disabled)
3) Delete ALL of the plugins in wp-content/plugins and wp-content/mu-plugins and re-install the Membership Plugin

After having no luck with previously mentioned, I am now quite annoyed and am not sure what to do next and am hoping that out of stupidity, I have missed something!

Thanks for the help!