Index: wp-admin/post.php
===================================================================
--- wp-admin/post.php	(revision 11901)
+++ wp-admin/post.php	(working copy)
@@ -147,7 +147,7 @@
 		$last_user_name = $last_user ? $last_user->display_name : __('Somebody');
 		$message = sprintf( __( 'Warning: %s is currently editing this post' ), esc_html( $last_user_name ) );
 		$message = str_replace( "'", "\'", "<div class='error'><p>$message</p></div>" );
-		add_action('admin_notices', create_function( '', "echo '$message';" ) );
+		add_action('admin_notices', create_function( "\$html = '$message'", 'echo $html;' ) );
 	} else {
 		wp_set_post_lock( $post->ID );
 		wp_enqueue_script('autosave');