Fatal error with Membership beta plugin

I installed the beta version of Membership to get around the issue with categories, and that works fine, but now I'm having a strange issue while updating a User Profile for and administrator level.

When I open my profile, or any administrator profile, the bottom of the page never displays. The page is cutoff after "Your Main Site." This means I can't see the Update button and make any profile edits.

Subscriber level profiles are unaffected. I have not tested other levels.

Here's what's displaying in the source.

<h3>Your Main Site</h3>
	<table class="form-table">
		<th><label for="description">Select Main Site</label></th>
						<select name='supporter_blog'>

			<br />
<b>Fatal error</b>:  Call to undefined function  get_blog_details() in <b>/home/xxxx/radiologylouisville.com/wp-content/plugins/membership/membershipincludes/plugins/supporter.php</b> on line <b>72</b><br />

I'm using WordPress 3.1 and Canvas theme from WooThemes. The site address is http://radiologylouisville.com/, but everyone on the front seems to be working.

Any sugestions?

Thank you.