By default the X Theme dos not include shortcode support for their topbar display element. In order to add shortcode support, you need to create a child theme, and place this new code in the _topbar.php file. This fix isn’t Memberium specific and will enable all shortcodes for the top bar.
Memberium Monthly User Webinar – April 2014: Building Successful Membership sites with Memberium
A Memberium plugin update released this past week (v2.166) could be causing some issues on your site. If you manually upgrade Membeirum to version 2.171 that should fix the issue for you.
This guide will show you how to allow your members to set their own password when placing an order through an Infusionsoft order form.