From the menu go to Tools, Security, User And Group Permissions.
IN the Dialog box there are two windows. Under the one on the right is a combo box labled object type. Drop that down to database (you will have to scroll up).
See if the admin user has administer permission. If not, someone has locked down the file so not just anyone can create objects in it. You should find the person who created the database and see about getting him to give you permission.
If however the author is long gone and you are a moral user of the system and should be able to access the entire database, then you can TRY to import all objects from the database into a new one. If you are LUCKY the admin user has read design permissions to all the objects and read data permissions for tables. By importing all the objects into a fresh file, you are the owner of the objects and get the default permissions for everything.
If you are UNLUCKY you don't have the necessary permissions and everything is locked down so tight that you can't import all the tables out or maybe some other objects. You MIGHT LOSE any database object in the new file. So if you go down this path, don't delete the original file.