View report error (IIS6 + Report 6.1.12.611)

[Dev]

Dear All,

Any help I would every appreciate.

I'm using IIS6, .Net4 32bit, Telerik web control and report version 6.1.12.611.

There are 4 params in the reports. 2 are hidden and 2 are datetime params.
I have checked my cookies, all have values.

I call this code to view the report:

Dim report As New Telerik.Reporting.InstanceReportSource
report.ReportDocument = New ReportHistory

With report.Parameters
    .Add("pUserName", Request.Cookies("username").Value)
    .Add("pUserID", Request.Cookies("senderid").Value)
    .Add("pFromDate", Now.Date.AddDays(-30))
    .Add("pToDate", Now.Date)
End With

ReportViewer.ReportSource = report
ReportViewer.RefreshReport()

Most of time I get the following error. 

Object reference not set to an instance of an object.

at Telerik.Reporting.Processing.ParametersManager`1..ctor(IReportDocument definition, ICollection`1 parameters)
at Telerik.ReportViewer.WebForms.ParametersPage.get_ParamsManager()
at Telerik.ReportViewer.WebForms.ParametersPage.CreateChildControls()
at System.Web.UI.Control.EnsureChildControls()
at Telerik.ReportViewer.WebForms.ParametersPage.OnPreLoad(EventArgs e)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

OR

Report is unavailable or session has expired (rarely have this error)

[Steve]

Hello,

Are you using out-proc session by any chance? Please upgrade to the latest internal build (v.6.1.12.621) and if the problem persists, please open a support ticket and attach a sample project that exhibits the problem. Once we review it, we would be able to provide you with more information.

Regards,
Steve
the Telerik team