Index: wp-admin/includes/file.php
===================================================================
--- wp-admin/includes/file.php	(revision 33310)
+++ wp-admin/includes/file.php	(working copy)
@@ -454,7 +454,7 @@
 	if ( ! $url )
 		return new WP_Error('http_no_url', __('Invalid URL Provided.'));
 
-	$tmpfname = wp_tempnam($url);
+	$tmpfname = wp_tempnam( parse_url( $url, PHP_URL_PATH ) );
 	if ( ! $tmpfname )
 		return new WP_Error('http_no_file', __('Could not create Temporary file.'));