Accessing Std Function from Custom Responsibility

Submenu Item Instance Navigation Menu Agent User lives under std Responsibility Oracle Installed Base Agent User. I have successfully added the submenu to my custom Responsibility. Function Item Instances exists under that menu. When I access function Item Instances under Responsibility Oracle Installed Base Agent User, the form displays successfully. When i try and access the same function under my custom Responsibility I get error: You do not have access to Systems page, please contact System Administrator. See attached screenshots.

Does anyone know what I have to have in place for the function Item Instances to work successfully from a custom Responsibility? Responses much appreciated.