diff --git a/product/ERP5Type/dynamic/lazy_class.py b/product/ERP5Type/dynamic/lazy_class.py
index 67b1e185b028aef4d71ecee3e4ae80c5cd173115..b3628a9b58f52c3e32242498e25b07b3d093cfac 100644
--- a/product/ERP5Type/dynamic/lazy_class.py
+++ b/product/ERP5Type/dynamic/lazy_class.py
@@ -202,6 +202,7 @@ class PortalTypeMetaClass(GhostBaseMetaClass):
       try:
         class_definition = generatePortalTypeClass(portal_type)
       except AttributeError:
+        import traceback; traceback.print_exc()
         LOG("ERP5Type.Dynamic", WARNING,
             "Could not access Portal Type Object for type %r"
             % portal_type, error=sys.exc_info())