Problems with DataAdapter.Update ( )

When I push the Edit DataGrid button above the DataGrid, I get a DataGrid where every row and cell are
in EditMode.

But when I push the Update DataGrid button above the dataGrid, only the first row in the dataset is
updated in the database, and then a a System.FormatExeption, saying: "Index (zero based) must be greater
than or equal to zero and less than the size of the argument list." is thrown.

My button update code is as follows:

public void UpdateDataGrid_Click(object sender, System.EventArgs e)
{
            try
            {
                DataRowCollection dr;
                DataTable dt = dsProductParameter.ProductParameter;
                dr = dt.Rows;

                for (int i = 0; i < ProductParameterGrid.Items.Count; i++)
                {
                    // Copy values from datagrid
                    dr[i]["ID"] = ((TextBox)ProductParameterGrid.Items[i].Cells[2].Controls[3]).Text;
                    dr[i]["Name"] = ((TextBox)ProductParameterGrid.Items[i].Cells[3].Controls[3]).Text;
                    dr[i]["Description"] = ((TextBox)ProductParameterGrid.Items[i].Cells[4].Controls[3]).Text;
                    dr[i]["PropertyValue"] = ((TextBox)ProductParameterGrid.Items[i].Cells[5].Controls[3]).Text;
                    dr[i]["PropertyValueDataType"] = ((TextBox)ProductParameterGrid.Items[i].Cells[6].Controls[3]).Text;
                    dr[i]["PropertyValueUnitOfMeasure"] = ((TextBox)ProductParameterGrid.Items[i].Cells[7].Controls[3]).Text;
                }

                    dbcInterface.UpdateProductParameter(dsProductParameter);

                     ..........
}

My UpdateProductParameter( ) method code that fails is :

public void UpdateProductParameter(DSProductParameter ds)
{
     try
     {
           sqlDaProductParameter.Update(ds);
     }
     catch (System.Exception Se)
     {
                      .......
                }
}

What am I doing wrong?