Getting errors while doing with Encryption and decryption (please help)

HI

the following is the code from msdn site and but still not working and giving me some errors

as

 Error 1 'ASP.default2_aspx.GetTypeHashCode()': no suitable method found to override c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\encrypt_app\7988e4b8\23526576\App_Web_f0xxt4ad.4.cs 296 


Error 2 'ASP.default2_aspx.ProcessRequest(System.Web.HttpContext)': no suitable method found to override c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\encrypt_app\7988e4b8\23526576\App_Web_f0xxt4ad.4.cs 301 


Error 3 'ASP.default2_aspx' does not implement interface member 'System.Web.IHttpHandler.IsReusable' c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\encrypt_app\7988e4b8\23526576\App_Web_f0xxt4ad.4.cs 129 


Please HELP
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