程序中用了log4net，就不能启动。显示信息如下，大家看看
1，设置了web.congig
<?xml   version= "1.0 "   encoding= "utf-8 "   ?>
<configuration>
<configsections>
<section   name= "log4net "   type= "log4net.config.log4netconfigurationsectionhandler,   log4net "   />
</configsections>
<system.web>
<!--     DYNAMIC   DEBUG   COMPILATION
                    Set   compilation   debug= "true "   to   enable   ASPX   debugging.     Otherwise,   setting   this   value   to
                    false   will   improve   runtime   performance   of   this   application.  
                    Set   compilation   debug= "true "   to   insert   debugging   symbols   (.pdb   information)
                    into   the   compiled   page.   Because   this   creates   a   larger   file   that   executes
                    more   slowly,   you   should   set   this   value   to   true   only   when   debugging   and   to
                    false   at   all   other   times.   For   more   information,   refer   to   the   documentation   about
                    debugging   ASP.NET   files.
        -->
<compilation   defaultLanguage= "c# "   debug= "true "   />
<!--     CUSTOM   ERROR   MESSAGES
                    Set   customErrors   mode= "On "   or   "RemoteOnly "   to   enable   custom   error   messages,   "Off "   to   disable.  
                    Add   <error>   tags   for   each   of   the   errors   you   want   to   handle.

                    "On "   Always   display   custom   (friendly)   messages.
                    "Off "   Always   display   detailed   ASP.NET   error   information.
                    "RemoteOnly "   Display   custom   (friendly)   messages   only   to   users   not   running  
                      on   the   local   Web   server.   This   setting   is   recommended   for   security   purposes,   so  
                      that   you   do   not   display   application   detail   information   to   remote   clients.
        -->
<customErrors   mode= "RemoteOnly "   />