Index: wp-includes/feed.php
===================================================================
--- wp-includes/feed.php	(revision 10670)
+++ wp-includes/feed.php	(working copy)
@@ -534,6 +534,14 @@
 	return apply_filters( 'feed_content_type', $content_type, $type );
 }
 
+/**
+ * Build SimplePie object based on RSS or Atom feed from URL.
+ *
+ * @since 2.8
+ *
+ * @param string $url URL to retrieve feed
+ * @return WP_Error|SimplePie WP_Error object on failure or SimplePie object on success
+ */
 function fetch_feed($url) {
 	require_once (ABSPATH . WPINC . '/class-feed.php');
 
@@ -545,6 +553,9 @@
 	$feed->init();
 	$feed->handle_content_type();
 
+	if($feed->error()) {
+		return new WP_Error('simplepie-error', $feed->error());
+	}
 	return $feed;
 }