Index: wp-includes/ms-settings.php
===================================================================
--- wp-includes/ms-settings.php	(revision 12918)
+++ wp-includes/ms-settings.php	(working copy)
@@ -81,14 +81,14 @@
 	} else {
 		$destination = 'http://' . $current_site->domain . $current_site->path . 'wp-signup.php?new=' . str_replace( '.' . $current_site->domain, '', $domain );
 	}
-	wp_redirect( $destination );
+	header( 'Location: ' . $destination );
 	die();
 }
 
 if ( ! defined( 'WP_INSTALLING' ) ) {
 	if ( $current_site && ! $current_blog ) {
 		if ( $current_site->domain != $_SERVER[ 'HTTP_HOST' ] ) {
-			wp_redirect( 'http://' . $current_site->domain . $current_site->path );
+			header( 'Location: http://' . $current_site->domain . $current_site->path );
 			exit;
 		}
 		$current_blog = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->blogs WHERE domain = %s AND path = %s", $current_site->domain, $current_site->path ) );