OK, here it goes
Calling ASPX throw thin one to system event log
Event code: 3007 
Event message: A compilation error has occurred. 
Event time: 11/12/2011 1:36:47 PM 
Event time (UTC): 11/12/2011 1:36:47 PM 
Event ID: 9dc33cb3a0964d0185ec404ecb511311 
Event sequence: 37 
Event occurrence: 3 
Event detail code: 0  
Application information: 
    Application domain: /UWS/{A22C128F-2878-44E5-8BF4-49A1BFA893FB}-2-129655779666406250 
    Trust level: Full 
    Application Virtual Path: / 
    Application Path: C:\DAT\_mixdev\ZEE-PC\ 
    Machine name: ZEE-PC  
Process information: 
    Process ID: 3416 
    Process name: UWS.AppHost.Clr4.AnyCPU.exe 
    Account name: NT AUTHORITY\NETWORK SERVICE  
Exception information: 
    Exception type: HttpCompileException 
    Exception message: c:\SYS\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\ba2f3259\9e7018bb\App_Web_test1.aspx.288c0f4c.tjcegolx.0.vb : (0): error BC31007: Unable to open module file 'c:\SYS\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\ba2f3259\9e7018bb\App_Web_test1.aspx.288c0f4c.tjcegolx.0.vb': System Error &Hc0000005& (Visual Basic internal compiler error)
   at System.Web.Compilation.AssemblyBuilder.Compile()
   at System.Web.Compilation.BuildProvidersCompiler.PerformBuild()
   at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath)
   at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
   at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
   at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean throwIfNotFound)
   at System.Web.Compilation.BuildManager.CreateInstanceFromVirtualPath(VirtualPath virtualPath, Type requiredBaseType, HttpContext context, Boolean allowCrossApp)
   at System.Web.UI.PageHandlerFactory.GetHandlerHelper(HttpContext context, String requestType, VirtualPath virtualPath, String physicalPath)
   at System.Web.UI.PageHandlerFactory.System.Web.IHttpHandlerFactory2.GetHandler(HttpContext context, String requestType, VirtualPath virtualPath, String physicalPath)
   at System.Web.HttpApplication.MapHttpHandler(HttpContext context, String requestType, VirtualPath path, String pathTranslated, Boolean useAppConfig)
   at System.Web.HttpApplication.MapHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)  
Request information: 
    Request URL: 
http://127.0.0.1/_test/test1.aspx     Request path: /_test/test1.aspx 
    User host address: 127.0.0.1 
    User:  
    Is authenticated: False 
    Authentication Type:  
    Thread account name: NT AUTHORITY\NETWORK SERVICE  
Thread information: 
    Thread ID: 27 
    Thread account name: NT AUTHORITY\NETWORK SERVICE 
    Is impersonating: False 
    Stack trace:    at System.Web.Compilation.AssemblyBuilder.Compile()
   at System.Web.Compilation.BuildProvidersCompiler.PerformBuild()
   at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath)
   at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
   at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate)
   at System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean throwIfNotFound)
   at System.Web.Compilation.BuildManager.CreateInstanceFromVirtualPath(VirtualPath virtualPath, Type requiredBaseType, HttpContext context, Boolean allowCrossApp)
   at System.Web.UI.PageHandlerFactory.GetHandlerHelper(HttpContext context, String requestType, VirtualPath virtualPath, String physicalPath)
   at System.Web.UI.PageHandlerFactory.System.Web.IHttpHandlerFactory2.GetHandler(HttpContext context, String requestType, VirtualPath virtualPath, String physicalPath)
   at System.Web.HttpApplication.MapHttpHandler(HttpContext context, String requestType, VirtualPath path, String pathTranslated, Boolean useAppConfig)
   at System.Web.HttpApplication.MapHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)  
Custom event details: