No Suitable method found to override

 Error    52    'ASP._..................aspx.GetTypeHashCode()': no suitable method found to override    c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\.............\18b5a5e4\6b9c8f5a\App_Web_nlbd7ihb.18.cs    888    

 
Error    53    'ASP............._aspx.ProcessRequest(System.Web.HttpContext)': no suitable method found to override    c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\................._1\18b5a5e4\6b9c8f5a\App_Web_nlbd7ihb.18.cs    893   
 
 
Error    54    'ASP............_aspx' does not implement interface member 'System.Web.IHttpHandler.IsReusable'    c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\....................... ...