undefined $_type on successful table rename

tbl_operations.php

@@ -190,6 +190,9 @@ unset($reread_info);
 require_once './libraries/tbl_links.inc.php';
 
 if (isset($result)) {
+    // set to success by default, because result set could be empty 
+    // (for example, a table rename)
+    $_type = 'success';
     if (empty($_message)) {
         $_message = $result ? $strSuccess : $strError;
         // $result should exist, regardless of $_message