Apply button not working In Sharepoint Integrated mode

Env:- SSRS 2008 R2 with Sharepoint 2010

For some report users, the Apply button is not working (SharePoint integrated mode).

After they select all the parameters in report and hit apply button , the page remain blanks and nothing happens.

This issue is experienced by certain user only.

When i checked the ULS log i found this during that duration

Process                                     Category                           Category          EventID

ReportingServicesService.Exe    Sharepoint Foundation      Database              4ohq

Site Enumeration Stack:   at Microsoft.SharePoint.Administration.SPSiteCollection.get_Count()    

at Microsoft.ReportingServices.SharePoint.ObjectModel.RSSPBaseCollection.get_Count()    

at Microsoft.ReportingServices.SharePoint.Server.SharePointPropertyProvider.GetProperty(String propertyName)    

at Microsoft.ReportingServices.SharePoint.Server.SharePointPropertyProvider.GetSystemUrl()    

at Microsoft.ReportingServices.Library.GetSystemPropertiesAction.PerformActionNow()   

 at Microsoft.ReportingServices.Library.RSSoapAction`1.Execute()   

 at Microsoft.ReportingServices.WebServer.ReportingService2005Impl.GetSystemProperties(Property[] Properties, Property[]& Values)   

 at Microsoft.ReportingServices.WebServer.ReportingServiceSPImpl.GetSystemProperties(Property[] Properties, Property[]& Values)  

 at Microsoft.ReportingServices.WebServer.ReportingService2010Impl.GetSystemProperties(Property[] Properties, Property[]& Values)    

at Microsoft.ReportingServices.WebServer.ReportingService2010.GetSystemProperties(Property[] Properties, Property[]& Values)    

at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)    

at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)   

 at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)  

 at System.Web.Services.Protocols.LogicalMethodInfo.Invoke(Object target, Object[] values)    

at System.Web.Services.Protocols.WebServiceHandler.Invoke()    

at System.Web.Services.Protocols.WebServiceHandler.CoreProcessRequest()   

 at System.Web.Services.Protocols.SyncSessionlessHandler.ProcessRequest(HttpContext context)    

at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()   

 at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)    

at System.Web.HttpApplication.ApplicationStepManager.ResumeSteps(Exception error)    

at System.Web.HttpApplication.System.Web.IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData)   

 at System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr)    

at System.Web.HttpRuntime.ProcessRequestNoDemand(HttpWorkerRequest wr)   

 at System.Web.HttpRuntime.ProcessRequest(HttpWorkerRequest wr)    

at ReportingServicesHttpRuntime.RsHttpRuntime.ProcessRequest(IRsHttpPipeline rsHttpPipeline) 

Can somebody please help on this.

Thanks,

Sandeep

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