[Resolvido] Erro Update

Pessoal, esta dando erro no meu update, mas não sei o que é...

Obrigado!

using System;
using System.Collections.Generic;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace WindowsFormsApplication2
{
public partial class Form2 : Form
{
#region Conexão

 SqlConnection sqlCoon = null;
 private string strCoon = @"Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\Elisângela\Documents\Visual Studio 2010\Projects\WindowsFormsApplication2\WindowsFormsApplication2\bd\Funcionarios.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";
 private string _Sql = string.Empty;
 string saida = "";
 string id = "";
 DateTime agora = DateTime.Now;

 #endregion

 public Form2()
 {
 InitializeComponent();
 }

 private void button1_Click(object sender, EventArgs e)
 {
 Application.Exit();

 }

 public void Form2_Load(object sender, EventArgs e)
 {

 sqlCoon = new SqlConnection(strCoon);
 sqlCoon.Open();

 _Sql = "SELECT TOP 1 [idponto], [Funcionario], [Entrada], [saida] FROM Ponto WHERE @cpf = Funcionario ORDER BY idponto DESC";
 SqlCommand cmd = new SqlCommand(_Sql, sqlCoon);
 string user = "";
 user = "41398039837";

 cmd.Parameters.Add("@cpf", SqlDbType.VarChar).Value = user;

 SqlDataReader dr = cmd.ExecuteReader();

 while (dr.Read())
 {

 id = dr[0].ToString();
 saida = dr[3].ToString();
 }

 lbcpf.Text = id + "-" + saida;
 if (saida == "")
 {
 dr.Dispose();
 testDB();

 }
 else
 {

 //MessageBox.Show("Existem dados na Saída"+"-"+ agora.ToLongDateString());
 //_Sql = "INSERT INTO Ponto, (Funcionario, Entrada) VALUES (@func, @entrada)";
 //SqlCommand objcmd = new SqlCommand(_Sql, sqlCoon);
 //objcmd.Parameters.Add("@func", SqlDbType.VarChar).Value = "41398039837";
 //objcmd.Parameters.Add("@entrada", SqlDbType.VarChar).Value = DataHora.ToShortTimeString();

 }

 }

 public bool update(ArrayList p_arrupdate) {

 MessageBox.Show("Saída Vazia");

 _Sql = "UPDATE TABLE Ponto SET Saida=@saida WHERE idponto=@id";

 SqlCommand objcmd = new SqlCommand(_Sql, sqlCoon);

 objcmd.Parameters.Add(new SqlParameter("@saida", p_arrupdate[0]));
 objcmd.Parameters.Add(new SqlParameter("@id", p_arrupdate[1]));

 objcmd.ExecuteNonQuery();
 sqlCoon.Close();
 return true;

 }
 public void testDB(){

 Update();

 ArrayList arr = new ArrayList();
 arr.Add(agora.ToShortTimeString());
 arr.Add(1);

 if (update(arr))
 {

 MessageBox.Show("Saída marcada com sucesso");

 }
 else {

 MessageBox.Show("A Saída não foi marcada", "Erro");

 }

 }

 }
}