什么是：标准表达式中数据类型不匹配？我看不懂！

[qiaov]

下面是源代码的一部分，错误已经标出来了。

<%@ Page Language="C#" ContentType="text/html" ResponseEncoding="gb2312" Debug="True" %>
<%@ Import NameSpace = "System" %>
<%@ Import NameSpace = "System.Data" %>
<%@ Import NameSpace = "System.Data.OleDb" %>
<Script language="c#" runat="server">
OleDbConnection myConn;
string strSQL;
public void Page_Load(Object src, EventArgs e)
{
string strConn = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" + Server.MapPath(".\\Vlink.mdb");
myConn = new OleDbConnection(strConn);
myConn.Open();

//Record Page Visit
//Get Date Serials
DateTime myDate = DateTime.Now;
string myDaySerials = myDate.Year.ToString();
if(myDate.Month.ToString().Length < 2)
myDaySerials += "0" + myDate.Month.ToString();
else
myDaySerials += myDate.Month.ToString();
if(myDate.Day.ToString().Length < 2)
myDaySerials += "0" + myDate.Day.ToString();
else
myDaySerials += myDate.Day.ToString();
//Get Over

string sqlClick = "Select [Clicks] From [Counter] Where id=1";
string sqlUpdate = "Update [Counter] Set [Clicks]=[Clicks]+1 Where id=1";

string sInsert = "Insert Into [Counter] ([Clicks], [DaySerial]) Values (1, " + myDaySerials + ")";
string sUpdate = "Update [Counter] Set [Clicks]=[Clicks]+1 Where [DaySerial] = '" + myDaySerials + "'";
string sClick = "Select [Clicks] From [Counter] Where [DaySerial] = '" + myDaySerials + "'";

//Update Database start
//1.Clicks
OleDbCommand myComm = new OleDbCommand(sqlUpdate, myConn);
myComm.ExecuteNonQuery();
myComm.CommandText = sqlClick;
OleDbDataReader myReader = myComm.ExecuteReader();
if(myReader.Read())
{
Clicks.Text = "<FONT COLOR='Red'>" + myReader["Clicks"].ToString() + "</FONT>";
}
else
{
Clicks.Text = "<FONT COLOR='Red'>Not Found!</FONT>";
}
myReader.Close();
//2.TodayClicks
try{
myComm.CommandText = sUpdate;
myComm.ExecuteNonQuery();
}
catch(Exception myError)
{
myComm.CommandText = sInsert;
myComm.ExecuteNonQuery();
}
myComm.CommandText = sClick;
//###############################################
myReader = myComm.ExecuteReader();//####出错的位置！！
//###############################################
if(myReader.Read())
{
TodayClicks.Text = "<FONT COLOR='Red'>" + myReader["Clicks"].ToString() + "</FONT>";
}
else
{
TodayClicks.Text = "<FONT COLOR='Red'>Not Found!</FONT>";
}
myReader.Close();

//Page Visit Over
......