Parser Error 是什么错误？

[Ruby_nenu]

是在调试web service时显示的错误，代码是按照书上给的打下来的， 如下：

<%@ WebService Language = "C#" Class = "ClacService" %>

using System;
using System.Web.Services;

[WebService (Name = "Calculator Web Service", Description = "Performs simple math over the Web")]

class CalcService
{
[WebMethod (Description = "Computer the sum of two integers")]
public int Add ( int a, int b)
{
return a+b;
}

[WebMethod(Description = "Computes the difference between two integers")]
public int Subtract (int a, int b)
{
return a - b;
}
}


在浏览器上输入地址后提示如下：
Server Error in '/' Application.
--------------------------------------------------------------------------------

Parser Error
Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.

Parser Error Message: Could not create type 'ClacService'.

Source Error:


Line 1:
Line 2:
Line 3: using System;


Source File: /calc.asmx Line: 1

本人今天才开始学这个玩意，请各位高人指教～