Index: wp-admin/includes/media.php
===================================================================
--- wp-admin/includes/media.php	(revision 8415)
+++ wp-admin/includes/media.php	(working copy)
@@ -102,7 +102,7 @@
 	$file = wp_handle_upload($_FILES[$file_id], $overrides);
 
 	if ( isset($file['error']) )
-		return new wp_error( 'upload_error', $file['error'] );
+		return new WP_Error( 'upload_error', $file['error'] );
 
 	$url = $file['url'];
 	$type = $file['type'];
@@ -142,7 +142,7 @@
 	$file = wp_handle_sideload($file_array, $overrides);
 
 	if ( isset($file['error']) )
-		return new wp_error( 'upload_error', $file['error'] );
+		return new WP_Error( 'upload_error', $file['error'] );
 
 	$url = $file['url'];
 	$type = $file['type'];