diff --git a/lib/zin/zentao/zentao.func.php b/lib/zin/zentao/zentao.func.php
index ef13d52b69..b9b36815a7 100644
--- a/lib/zin/zentao/zentao.func.php
+++ b/lib/zin/zentao/zentao.func.php
@@ -22,12 +22,15 @@ class html extends \html
 {
 }
 
-class commonModel extends \commonModel
+if($config->installed)
 {
-}
+    class commonModel extends \commonModel
+    {
+    }
 
-class common extends \commonModel
-{
+    class common extends \commonModel
+    {
+    }
 }
 
 /**