diff -r f507feede89a -r 09a1c134465b web/wp-includes/ms-settings.php
--- a/web/wp-includes/ms-settings.php	Wed Dec 19 12:35:13 2012 -0800
+++ b/web/wp-includes/ms-settings.php	Wed Dec 19 17:46:52 2012 -0800
@@ -126,6 +126,8 @@
 $wpdb->set_prefix( $table_prefix, false ); // $table_prefix can be set in sunrise.php
 $wpdb->set_blog_id( $current_blog->blog_id, $current_blog->site_id );
 $table_prefix = $wpdb->get_blog_prefix();
+$_wp_switched_stack = array();
+$switched = false;
 
 // need to init cache again after blog_id is set
 wp_start_object_cache();