diff --git a/xmlrpc.php b/xmlrpc.php
index e5473e0b9..045acba76 100644
--- a/xmlrpc.php
+++ b/xmlrpc.php
@@ -6,7 +6,8 @@ define('XMLRPC_REQUEST', true);
 $_COOKIE = array();
 
 # fix for mozBlog and other cases where '<?xml' isn't on the very first line
-$HTTP_RAW_POST_DATA = trim($HTTP_RAW_POST_DATA);
+if ( isset($HTTP_RAW_POST_DATA) )
+	$HTTP_RAW_POST_DATA = trim($HTTP_RAW_POST_DATA);
 
 include('./wp-config.php');