diff --git a/include/errors/class_SimplePluginError.inc b/include/errors/class_SimplePluginError.inc
index ea2eb5854c7639cd2c6f204047202cfa00852b2a..3fdf05a8865176095cd1cfc99898c3003928a8e0 100644
--- a/include/errors/class_SimplePluginError.inc
+++ b/include/errors/class_SimplePluginError.inc
@@ -45,9 +45,11 @@ class SimplePluginError extends FusionDirectoryError
       if ($origin instanceof SimpleTab) {
         $this->tab    = $origin;
         $this->object = $this->tab->parent;
-      } else {
+      } elseif ($origin instanceof simpleTabs) {
         $this->tab    = NULL;
         $this->object = $origin;
+      } else {
+        trigger_error('Invalid origin of class '.get_class($origin));
       }
     }
   }