Index: functions.php
===================================================================
--- functions.php	(revision 45109)
+++ functions.php	(working copy)
@@ -2964,6 +2964,8 @@
  */
 function wp_die( $message = '', $title = '', $args = array() ) {
 
+	global $wp_query;
+
 	if ( is_int( $args ) ) {
 		$args = array( 'response' => $args );
 	} elseif ( is_int( $title ) ) {
@@ -3008,9 +3010,9 @@
 		 */
 		$function = apply_filters( 'wp_die_xmlrpc_handler', '_xmlrpc_wp_die_handler' );
 	} elseif ( wp_is_xml_request()
-		|| function_exists( 'is_feed' ) && is_feed()
-		|| function_exists( 'is_comment_feed' ) && is_comment_feed()
-		|| function_exists( 'is_trackback' ) && is_trackback() ) {
+		|| isset( $wp_query ) && function_exists( 'is_feed' ) && is_feed()
+		|| isset( $wp_query ) && function_exists( 'is_comment_feed' ) && is_comment_feed()
+		|| isset( $wp_query ) && function_exists( 'is_trackback' ) && is_trackback() ) {
 		/**
 		 * Filters the callback for killing WordPress execution for XML requests.
 		 *
 EOD;