Problem finding table index 0

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C#

ADO.NET

hey guys me again.

got a little problem with the code finding the table with the index of 0 (zero)

i dont see the problem my self as i am using only one table.

this is the code for my update function:

private void UpdateBTN_Click(object sender, EventArgs e)
        {
            using (conn)
            {
                da.UpdateCommand = new SqlCommand("UPDATE Book SET Title = @title, AuthorFirstName = @authorFirstName, AuthorSurname = @authorsurname, AquisitionDate = @aquisitiondate, PublisherName = @publishername,
 PublisherCity = @publishercity, PublishingDate = @publishingdate,
 ISBN = @isbn, DDClassification = @ddclassification WHERE BookID = @ID", conn);

da.UpdateCommand.Parameters.Add("@title", SqlDbType.VarChar).Value = titleTB.Text;
da.UpdateCommand.Parameters.Add("@authorFirstName", SqlDbType.VarChar).Value = authorFirstNameTB.Text;
da.UpdateCommand.Parameters.Add("@authorsurname", SqlDbType.VarChar).Value = authorSurNameTB.Text;
da.UpdateCommand.Parameters.Add("@aquisitiondate", SqlDbType.Date).Value = aquisitionDateTB.Text.ToString();
da.UpdateCommand.Parameters.Add("@publishername", SqlDbType.VarChar).Value = publisherNameTB.Text;
da.UpdateCommand.Parameters.Add("@publishercity", SqlDbType.VarChar).Value = publisherCityTB.Text;
da.UpdateCommand.Parameters.Add("@publishingdate", SqlDbType.Date).Value = publishingDateTB.Text.ToString();
da.UpdateCommand.Parameters.Add("@isbn", SqlDbType.VarChar).Value = ISBNTB.Text;
da.UpdateCommand.Parameters.Add("@ddclassification", SqlDbType.VarChar).Value = DDClassificationTB.Text;
da.UpdateCommand.Parameters.Add("@ID", SqlDbType.Int).Value = ds.Tables[0].Rows[tblNamesBS.Position][0];// right here @ ds.Tables[0]
conn.Open();
da.UpdateCommand.ExecuteNonQuery();
       }
        }

error is on last update parameter, any idea why it is throwing this exception?

message is:
IndexOutOfRangeException was unhandled

Cannot find table 0.

Regards
Matt.