SQL Server :: SqlDataAdapter Update Returns 0 Records?

using ASP.NET 2.0 SqlDataAdapter update returns 0 records. I have a simple application that stores Passenger's ticket info in a sql database.

when a user clicks "Create Reservation" I add a Passenger Information (name, destination, PNR) to dataset
and save dataset in ViewState.

Then when user clicks update, I pull the dataset from viewState and try to update database. The update is returning 0. what i am doing incorrectly?

protected void btn_CreateReservation_Click(object sender, EventArgs e)
{
DataRow dr ;
dr = dt.NewRow();
dr["Name"] = txtBox_Name.Text; dr["Destination"] = txtBox_Destination.Text;
dr["PNR"] = Convert.ToInt32(txtbox_PNR.Text); dt.Rows.Add(dr);
dt.AcceptChanges();
ViewState["MyTable"] = dsPassengers;

[Code]....