Index: wp-includes/class-phpmailer.php
===================================================================
--- wp-includes/class-phpmailer.php	(revision 5845)
+++ wp-includes/class-phpmailer.php	(working copy)
@@ -457,7 +457,7 @@
      * @return bool
      */
     function SmtpSend($header, $body) {
-        include_once($this->PluginDir . "class.smtp.php");
+        include_once($this->PluginDir . "class-smtp.php");
         $error = "";
         $bad_rcpt = array();