出错信息如下，请老手诊断。
Server Error in '/' Application.
Security Exception
Description: The application attempted to perform an operation not allowed
by the security policy. To grant this application the required permission
please contact your system administrator or change the application's trust
level in the configuration file.
Exception Details: System.Security.SecurityException: Request failed.
Source Error:
An unhandled exception was generated during the execution of the current web
request. Information regarding the origin and location of the exception can
be identified using the exception stack trace below.
Stack Trace:
[SecurityException: Request failed.]
YJ.Common.Utils..cctor() +0
Version Information: Microsoft .NET Framework Version:2.0.50727.5446; ASP.
NET Version:2.0.50727.5420
