If you deleted it directly from the db but did not delete any of the relating records then you can have an orphaned area like this. The only way to get it back to the way it was before is to restore the record in the db. If you can't do this manually then you may need to do this by getting the sql to insert the record from the install > scripts > db.sql file. In this file are all of the inserts statements for the various content, you can just look for the record that you are missing and execute the sql for it. You could also just clear the tables in the db except for the wa_settings and re-import the entire sql file except for the wa_settings table. This would reset the data back to it's default state.