Index: wp-includes/comment.php
===================================================================
--- wp-includes/comment.php	(revision 10195)
+++ wp-includes/comment.php	(working copy)
@@ -1261,6 +1261,9 @@
 
 	$contents = $response['body'];
 
+	if ( is_wp_error( $contents ) )
+		return false;
+
 	$pingback_link_offset_dquote = strpos($contents, $pingback_str_dquote);
 	$pingback_link_offset_squote = strpos($contents, $pingback_str_squote);
 	if ( $pingback_link_offset_dquote || $pingback_link_offset_squote ) {