diff --git a/inc/cache.php b/inc/cache.php
index 5eac949345808328231dca38938410a9358c468d..8453fe3e99ce91823de95f99bb6c4b83bb1b4554 100644
--- a/inc/cache.php
+++ b/inc/cache.php
@@ -16,6 +16,7 @@ class cache {
     //   used by _useCache to determine cache validity
 
     var $_event = '';       // event to be triggered during useCache
+    var $_time;
 
     function cache($key,$ext) {
         $this->key = $key;