my project has been already running but ringht now i have getting mention error. please help to remove this.

Server Error in '/sfty_Lead_lag' Application.

Compilation Error

Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately. Compiler Error Message: CS0103: The name 'department' does not exist in the current context Source Error:

Line 54:                 txtEMPNO.Text = "" + EMPNO + "";
Line 55:                 txtNAME.Text = "" + EmpName + "";
Line 56:                 txtDEPARTMENT.Text = "" + department + "";
Line 57:             }
Line 58: 

Source File: f:\Intranet\mejaitapps\sfty_Lead_lag\WebForm2.aspx.cs    Line: 56

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.3062.0

        protected void Page_Load(object sender, EventArgs e)
        {
            if (Session["EmpName"] == null)
            {
                Response.Redirect("login.aspx");
            }
            else
            {
                String EmplooyeId = Convert.ToString((int)Session["EMPNO"]);
                String EMPNO = Session["EMPNO"].ToString();
                String EmpName = Session["EmpName"].ToString();
                String department = Session["department"].ToString();
                txtEMPNO.Text = "" + EMPNO + "";
                txtNAME.Text = "" + EmpName + "";
                txtDEPARTMENT.Text = "" + department + "";
            }

            if (!Page.IsPostBack)
            {
                this.BindGrid();
                int currentYear = DateTime.Today.Year;
                ddl_Year.Items.Clear();
                // ddl_Year.Items.Add("Select");
                for (int i = 1; i >= 0; i--)
                {
                    int fy = currentYear - i;
                    int fy1 = fy + 1;
                    if (DateTime.Now.Date > Convert.ToDateTime(fy + "-03-31").Date)
                    {
                        ddl_Year.Items.Add(fy.ToString() + "-" + fy1.ToString());
                    }
                }
                txtDATE.Text = DateTime.Now.ToString();

                DateTime currentDate = DateTime.Now;
                List<ListItem> items = new List<ListItem>();
                items.Add(new ListItem
                {
                    Text = currentDate.AddMonths(-1).Month.ToString(),
                    Value = currentDate.AddMonths(-1).Month.ToString()
                });
                items.Add(new ListItem
                {
                    Text = currentDate.Month.ToString(),
                    Value = currentDate.Month.ToString()
                });
                ddl_Month.DataSource = items;
                ddl_Month.DataTextField = "Text";
                ddl_Month.DataValueField = "Text";
                ddl_Month.DataBind();
            }
            if (!IsPostBack)
            {
                string query = "select CountryId, CountryName from Countries";
                BindDropDownList(DropDownList2, query, "CountryName", "CountryId", "Select ");
                DropDownList3.Enabled = false;
                DropDownList3.Items.Insert(0, new ListItem("Select ", "0"));
            }
        }