Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 22995)
+++ wp-includes/functions.php	(working copy)
@@ -1538,6 +1538,10 @@
 			//   2) we are not switched, as ms_upload_constants() hardcodes
 			//      these constants to reflect the original blog ID.
 
+			// Do these look familiar?
+			$dir = ABSPATH . UPLOADS;
+			$url = trailingslashit( $siteurl ) . UPLOADS;
+
 			if ( defined( 'BLOGUPLOADDIR' ) )
 				$dir = untrailingslashit( BLOGUPLOADDIR );
 			$url = str_replace( untrailingslashit( UPLOADS ), 'files', $url );