BuddyPress update broke my site

I just updated WP to 3.2 and BP to 1.2.9. But I got this:

Downloading update from http://downloads.wordpress.org/plugin/buddypress.1.2.9.zip…
Unpacking the update…
Installing the latest version…
Deactivating the plugin…
Removing the old version of the plugin…
Plugin updated successfully.
Reactivating the plugin…

Fatal error: Call to undefined function is_site_admin() in /home/admin/public_html/[hidden]/wp-content/mu-plugins/moderation_framework.php on line 174

Is there any way to back out the BP update? What's the best fix?

Thanks,
Lee