You will have to check what the BindData function actually does. I think it is populating the GridView from a Sesssion and setting the PageIndex. Try setting the PageIndex after binding the GridView like this
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindData();
gvSummary.PageIndex = 0;
gvSummary.DataBind();
dlAnnoType.SelectedValue = "Agency Error";
}
}
P.S: this
is not needed here