try this
foreach (GridViewRow row in grdReports.Rows)
{
CheckBox chkSelectEmp = row.FindControl("chkSelect") as CheckBox;
if (chkSelectEmp .Checked == true)
{
Label lblEmpId = (Label )grdReports.Rows[rowIndex].Cells[6].FindControl("lblEmpRefId");
Session["EmpRefId"] = lblEmpId.Text.ToString();
}
}
here , you metion Cells[6] to Correct Index of "LblEmpRefId"