CRVS2010 WPF Viewer crashes

Hi All,

I have a simple crystal report which has one Group. The report also has a parmeter which is prompted.
When I view the report in a WPF viewer and select an item on the Group Tree the viewer crashes with a

"An unhandled exception of type 'System.StackOverflowException' occurred in CrystalDecisions.CrystalReports.Engine.dll"

I am using Crytsal 13.0.4.705.

thanks

my code...

Imports CrystalDecisions.CrystalReports.Engine
Imports CrystalDecisions.ReportSource

Public Class Form1
   Private _reportdoc As ReportDocument
   Private _viewer As SAPBusinessObjects.WPF.Viewer.CrystalReportsViewer

   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

      Dim fileName As String = "c:\users\5.0\Reports\sqlserver\X_Country.rpt"
      _viewer = Me.ReportContainer1.reportViewer
      Dim oreport = New ReportDocument
      oreport.Load(fileName, 0)

      With _viewer
         .IsEnabled = True
         .EnableToolTips = True
         .ShowOpenFileButton = False
         .ShowExportButton = True
         .ShowNextPageButton = True
         .ShowPrevPageButton = True
         .ShowPrintButton = True
         .ShowToggleSidePanelButton = True
         .ShowSearchTextButton = True
         .ToggleSidePanel = SAPBusinessObjects.WPF.Viewer.Constants.SidePanelKind.None
         .ShowRefreshButton = True
         .ShowGoToPageButton = True
         .ViewerCore.ReportSource = oreport
      End With
   End Sub
End Class