我有一个在线运行的web站点，时不时会出现在线人数下降的情况，网站情况：
基于.net 3.5，c#开发，部署环境：win server 2003， iis6.0 asp.net2.0。
检查在线下滑的时间段，发现iis服务器的中大量存在下述事件信息，类型为warning
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 6/22/2011 5:48:29 PM
Event time (UTC): 6/22/2011 10:48:29 AM
Event ID: 166b3c2bce9f4171a830d6fc9ffc58f9
Event sequence: 6002
Event occurrence: 3001
Event detail code: 0
Application information:
Application domain: /LM/W3SVC/1282155927/Root-2-129532126469053750
Trust level: Full
Application Virtual Path: /
Application Path: D:\web\request\
Machine name: GS_GN_04_WEB
Process information:
Process ID: 2312
Process name: w3wp.exe
Account name: NT AUTHORITY\NETWORK SERVICE
Exception information:
Exception type: TypeInitializationException
Exception message: The type initializer for 'Tank.Request.Global' threw an exception.
Request information:
Request URL: http://www.gn.zing.vn/CreateLogin.aspx
Request path: /CreateLogin.aspx
User host address: 123.30.133.144
User:
Is authenticated: False
Authentication Type:
Thread account name: NT AUTHORITY\NETWORK SERVICE
Thread information:
Thread ID: 9
Thread account name: NT AUTHORITY\NETWORK SERVICE
Is impersonating: False
Stack trace: at Tank.Request.Global..ctor()
at ASP.global_asax..ctor() in c:\windows\microsoft.net\Framework64\v2.0.50727\Temporary ASP.NET Files\root\b11f52b4\54c71dd4\App_global.asax.dr5yzzkb.0.cs:line 0
Custom event details:
For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
请问这是什么问题引发的啊？
另外我在global.asax.cs中实现了Application_Error()接口以捕获异常信息，结果发现类似这样的异常还是捕获不到，或者说是绝大多数时间不起效，只是很偶尔的时候起效。
以上问题，求高手指点。
