--- ./webfm.module	2009-08-19 17:44:14.000000000 +0200
+++ /var/www/acpadova4/sites/all/modules/webfm/webfm.module	2009-10-08 17:38:38.000000000 +0200
@@ -424,7 +424,7 @@ function webfm_nodeapi(&$node, $op, $tea
     case 'update':
       // If the user cannot access webfm, $_POST['attachlist'] is always empty
       // and therefore will delete existing attachments from the node.
-      if(user_access('access webfm')) {
+      if(user_access('access webfm') && array_key_exists('attachlist', $_POST)) {
         $files = explode(',', $_POST['attachlist']);
         webfm_dbupdate_attach($node->nid, $files);
       }