You've only just created a new DataSet so it's empty. You can't update a DataTable named "t003Akaun" in a DataSet that contains no tables.

Are you trying to retrieve data or save it? If you're retrieving data then you should becalling Fill, not Update. If you're saving then you need to have already retrieved that data into the DataTable. I'd suggest that you read some of the ADO.NET tutorials from the links in my signature.