Report viewer sub reports

Question

hi
I am trying to add parameter to subreports its showing error in sub report as follows
plz any body help me

Thanks
vinod

Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 10/14/2010 11:22:20 AM
Event time (UTC): 10/14/2010 5:52:20 AM
Event ID: fa6f1c20ba4a483981eedd7565f8899b
Event sequence: 6
Event occurrence: 1
Event detail code: 0
 
Application information:
    Application domain: 7c54f285-2-129315091351419235
    Trust level: Full
    Application Virtual Path: /WebSite3
    Application Path: D:\vinod\WebSite3\
    Machine name: WIN-0HF781JHR7G
 
Process information:
    Process ID: 5532
    Process name: WebDev.WebServer40.exe
    Account name: DOMAIN\vinodkumar.j
 
Exception information:
    Exception type: AspNetSessionExpiredException
    Exception message: ASP.NET session has expired or could not be found
   at Microsoft.Reporting.WebForms.ViewerDataOperation..ctor()
   at Microsoft.Reporting.WebForms.HttpHandler.GetHandler(String operationType)
   at Microsoft.Reporting.WebForms.HttpHandler.ProcessRequest(HttpContext context)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

 
 
Request information:
    Request URL: http://localhost:19000/WebSite3/Reserved.ReportViewerWebControl.axd?OpType=SessionKeepAlive&ControlID=e818047818d946e4b5ec1d9edc1c1dca&Mode=true
    Request path: /WebSite3/Reserved.ReportViewerWebControl.axd
    User host address: 127.0.0.1
    User: DOMAIN\vinodkumar.j
    Is authenticated: True
    Authentication Type: NTLM
    Thread account name: DOMAIN\vinodkumar.j
 
Thread information:
    Thread ID: 13
    Thread account name: DOMAIN\vinodkumar.j
    Is impersonating: False
    Stack trace:    at Microsoft.Reporting.WebForms.ViewerDataOperation..ctor()
   at Microsoft.Reporting.WebForms.HttpHandler.GetHandler(String operationType)
   at Microsoft.Reporting.WebForms.HttpHandler.ProcessRequest(HttpContext context)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
 
 
Custom event details: