Index: wp-includes/comment.php
===================================================================
--- wp-includes/comment.php	(revision 11001)
+++ wp-includes/comment.php	(working copy)
@@ -189,7 +189,7 @@
 	$key = md5( serialize( compact(array_keys($defaults)) )  );
 	$last_changed = wp_cache_get('last_changed', 'comment');
 	if ( !$last_changed ) {
-		$last_changed = time();
+		$last_changed = current_time('timestamp');
 		wp_cache_set('last_changed', $last_changed, 'comment');
 	}
 	$cache_key = "get_comments:$key:$last_changed";
@@ -1601,7 +1601,7 @@
 	if ( !$days_old )
 		return $posts;
 
-	if ( time() - strtotime( $posts[0]->post_date_gmt ) > ( $days_old * 24 * 60 * 60 ) ) {
+	if ( strtotime(gmdate("Y-m-d H:i:s")) - strtotime( $posts[0]->post_date_gmt ) > ( $days_old * 24 * 60 * 60 ) ) {
 		$posts[0]->comment_status = 'closed';
 		$posts[0]->ping_status = 'closed';
 	}
@@ -1632,7 +1632,7 @@
 
 	$post = get_post($post_id);
 
-	if ( time() - strtotime( $post->post_date_gmt ) > ( $days_old * 24 * 60 * 60 ) )
+	if ( strtotime(gmdate("Y-m-d H:i:s")) - strtotime( $post->post_date_gmt ) > ( $days_old * 24 * 60 * 60 ) )
 		return false;
 
 	return $open;