ARERR [5028] Unable to add a menu item because there are too many levels in the character menu. Character menus cannot exceed 15 levels. [Lotar's Wiki]

AR System Message Catalog

Menus can contain a maximum of 15 levels. You specified a menu that contains more than 15 levels at some point in its hierarchy.

ARERR [5028] Unable to add a menu item because there are too many levels in the character menu. Character menus cannot exceed 15 levels.