Hi Sabawoon,
The structure of the information map is cached inside the MA Application server, so changes that you make are not immediately available. To refresh the cache you can go into CI Studio -> Administration Workspace -> Business Contexts. Edit the business context and go to the Metadata tab and click "Clear Metadata Cache", log out and log in. For more detailed instructions you can take a look at the MA Users guide, Pg 48.
Regards
James