ParentItem Element will only work correctly if your setup meets these requirements:
- Up-to-date version of Joomla 2.5 or 3.x
- Up-to-date version of YOOtheme ZOO 3.0.x
- PHP 5.3+
- MySQL 5+
Important: I can only provide support for setups that:
- meet the above requirements;
- do not have extension files or Joomla! core files which have been altered in any way.
Easy to install and use, customisable.