[AccessD] MSysTables permissions

Hello Group,

on a .mdw secured database, i get an error:
Error 3033. You don't have permissions for Object MSysTables.

This error occurs when logging in as a user, when trying to use a commandbutton on a form. When logging in as administrator everything works fine.
When i look at the system Objects, i can't find MSysTables. 
Nothing about this at the Knowledge Base.
Where can i find this table and how is it possible that permissions need to be adjusted voor System Objects?

Pedro Janssen