各位大侠。帮我看看这程序出现了什么问题。。？

前台界面代码：
<%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="ReadNews.aspx.cs" Inherits="ReadNews" Title="Untitled Page" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
<script language="javascript" type="text/javascript">
<!--

function TABLE1_onclick() {

}

// -->
</script>
<table border="0" cellpadding="0" cellspacing="0" style="border-right: #cccccc 1px solid;
border-top: #cccccc 1px solid; border-left: #cccccc 1px solid; width: 95%;
border-bottom: #cccccc 1px solid" id="TABLE1" language="javascript" onclick="return TABLE1_onclick()" align=center>
<tr>
<td style="width: 100%; border-bottom: #00ff33 1px solid; height: 14px; background-color: #cccccc;" align=left>
您的位置：<asp:Label ID="lbl_class" runat="server"></asp:Label>－>系部介绍
</td>
</tr>
<tr>
<td style="width: 100%; height:15px">
<table border="0" cellpadding="0" cellspacing="0" style="width: 60%" align=center>
<tr>
<td style="border-bottom: #ffcc00 1px solid; height: 17px" align=center>
<asp:Label ID="lbl_title" runat="server"></asp:Label>
</td>
</tr>
</table>
</td>
</tr>
<tr>
<td style="width: 100%; height:14px" align=center>
<asp:Label ID="lbl_info" runat="server"></asp:Label>
</td>
</tr>
<tr>
<td style="width: 100px; height: 16px;">
</td>
</tr>
<tr>
<td style="width: 100%; height:14px" align=left>
       
<asp:Label ID="lbl_content" runat="server"></asp:Label>
</td>
</tr>
</table>
</asp:Content>




后台代码：

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;

public partial class ReadNews : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
int newsid = Convert.ToInt32(Request.QueryString["id"].ToString());

string setting = Convert.ToString(ConfigurationManager.ConnectionStrings["SqlServives"]);

SqlConnection conn = new SqlConnection(setting);

conn.Open();
string sql = "select A.Title,A.Content,A.Time,A.Author,A.Readcishu, B.pastemName from Body A ,Pastem B Where B.pastemID = A.pastemID And A.ID =" + newsid;

SqlCommand cmd = new SqlCommand(sql, conn);
SqlDataReader dr = cmd.ExecuteReader();
if (dr.Read())
{
lbl_class.Text = dr["pastemName"].ToString();
lbl_content.Text = dr["Content"].ToString();
lbl_title.Text = dr["Title"].ToString();
lbl_info.Text = "作者：" + dr["Author"].ToString() + " 时间：" + dr["Time"].ToString() + "阅读：" + dr["Readcishu"].ToString() + "次";
}
int m = Convert.ToInt32(dr["Readcishu"].ToString()) + 1;
conn.Close();
UpdataPo(newsid, m);
}
public void UpdataPo(int id, int m)
{
string settings = Convert.ToString(ConfigurationManager.ConnectionStrings["SqlServices"]);

SqlConnection myconn = new SqlConnection(settings);

myconn.Open();
string sql = "Update Body Set ReadCishu=" + m + " Where ID = " + id;

SqlCommand mycmd = new SqlCommand(sql, myconn);
mycmd.ExecuteNonQuery();
}
}

错误信息：
“/WebSite1”应用程序中的服务器错误。
--------------------------------------------------------------------------------

未将对象引用设置到对象的实例。
说明: 执行当前 Web 请求期间，出现未处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。

异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。

源错误:


行 15: protected void Page_Load(object sender, EventArgs e)
行 16: {
行 17: int newsid = Convert.ToInt32(Request.QueryString["id"].ToString());
行 18:
行 19: string setting = Convert.ToString(ConfigurationManager.ConnectionStrings["SqlServives"]);


源文件: d:\Documents\Visual Studio 2005\WebSites\WebSite1\ReadNews.aspx.cs 行: 17

堆栈跟踪:


[NullReferenceException: 未将对象引用设置到对象的实例。]
ReadNews.Page_Load(Object sender, EventArgs e) in d:\Documents\Visual Studio 2005\WebSites\WebSite1\ReadNews.aspx.cs:17
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +43
System.Web.UI.Control.OnLoad(EventArgs e) +73
System.Web.UI.Control.LoadRecursive() +52
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2184