http://weblogs.asp.net/scottgu/archive/2006/09/30/tip_2f00_trick_3a00_-guard-against-sql-injection-attacks.aspx

 <!-- Sys 관련 Error 메세지가 있을경우-->
    <httpHandlers>
      <remove verb="*" path="*.asmx"/>
      <add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
      <add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
      <add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" validate="false"/>
    </httpHandlers>
    <httpModules>
      <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
    </httpModules>

이것을 web.config에 붙이면 없어진다.

프로젝트 진행시 위와 같은 궁금점이 있을것이다.
아래의 내용을 참고해보자.

http://blogs.microsoft.co.il/blogs/maordavid/archive/2007/06/03/ASP.NET-2.0-_2D00_-Web-Site-vs-Web-Application-project.aspx