diff --git a/tiramisu/api.py b/tiramisu/api.py
index 3d8734e..48678a1 100644
--- a/tiramisu/api.py
+++ b/tiramisu/api.py
@@ -87,8 +87,8 @@ class CommonTiramisu(TiramisuHelp):
 
     async def _get_option(self,
                           connection) -> Any:
+        config_bag = self._option_bag.config_bag
         if not self._subconfig:
-            config_bag = self._option_bag.config_bag
             try:
                 subconfig, name = await config_bag.context.cfgimpl_get_home_by_path(self._option_bag.path,
                                                                                     config_bag,
@@ -101,7 +101,7 @@ class CommonTiramisu(TiramisuHelp):
             self._name = name
         option = self._option_bag.option
         if option is None:
-            option = await self._subconfig.cfgimpl_get_description().get_child(name,
+            option = await self._subconfig.cfgimpl_get_description().get_child(self._name,
                                                                                config_bag,
                                                                                self._subconfig.cfgimpl_get_path())
             self._option_bag.option = option
diff --git a/tiramisu/config.py b/tiramisu/config.py
index f350408..b80b150 100644
--- a/tiramisu/config.py
+++ b/tiramisu/config.py
@@ -64,11 +64,11 @@ class SubConfig:
                 (not isinstance(descr, (BaseOption, SynDynOptionDescription)) or
                  not descr.impl_is_optiondescription()):
             try:
-                msg = descr.impl_get_displayname()
+                msg = descr.impl_get_display_name()
             except AttributeError:
                 msg = descr
-            raise TypeError(_('"{0}" must be an optiondescription, not an {1}'
-                              ).format(msg, type(descr)))
+            raise TypeError(_('cannot create a sub config for "{0}" this is a "{1}", not an "OptionDescription"'
+                              ).format(msg, descr.__class__.__name__))
         self._impl_descr = descr
         self._impl_context = context
         self._impl_path = subpath