Crystal report navigation

I have a Crystal report that displays the result of two linked dropdownlists. The dropdownlist and report sub are nested in the page.ini sub while I have nothing in the page.load sub.
When i click the navigation button to go to the next page my report disapear. Can you help me to fix that? Here is my code:

Private Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
        If Not IsPostBack Then
            If Not Session("SUBCATID") Is Nothing Then
                FillCat()
                ConfigureCrystalReports()
                ShowRept()
            Else
                FillCat()
                ConfigureCrystalReports()
            End If
        End If
    End Sub

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

    End Sub

 Private Sub ConfigureCrystalReports()
        CrystalReportViewer.HasPageNavigationButtons = True
        'CrystalReportViewer.ToolbarImagesFolderUrl = "~/Images"
        CrystalReportViewer.HasExportButton = False
        CrystalReportViewer.HasCrystalLogo = False
        CrystalReportViewer.HasToggleGroupTreeButton = False
        CrystalReportViewer.HasViewList = False
        CrystalReportViewer.HasPrintButton = False
        CrystalReportViewer.HasDrillUpButton = False
        CrystalReportViewer.HasSearchButton = False
        CrystalReportViewer.HasGotoPageButton = False
        CrystalReportViewer.HasZoomFactorList = False
        CrystalReportViewer.DisplayToolbar = True
        CrystalReportViewer.BorderWidth = 2
        CrystalReportViewer.BorderColor = Drawing.Color.DarkGreen
        CrystalReportViewer.DisplayGroupTree = False
        CrystalReportViewer.DisplayPage = True
        CrystalReportViewer.BestFitPage = True
    End Sub

 Sub ShowRept()
        Dim cryRpt As New CrystalDecisions.CrystalReports.Engine.ReportDocument
        Dim CrTable As CrystalDecisions.CrystalReports.Engine.Table
        Dim crtableLogoninfos As CrystalDecisions.Shared.TableLogOnInfo
        cryRpt.Load(Server.MapPath("~/CrystalReports/Catalogue1.rpt"), CrystalDecisions.Shared.OpenReportMethod.OpenReportByTempCopy)

        For Each CrTable In cryRpt.Database.Tables
            crtableLogoninfos = CrTable.LogOnInfo
            With crtableLogoninfos.ConnectionInfo
                .ServerName = "MYSERVER"
                .DatabaseName = "MYDB"
                .UserID = "sa"
                .Password = "12345"
            End With
            CrTable.ApplyLogOnInfo(crtableLogoninfos)
        Next CrTable

             Dim crParameterFieldDefinitions As ParameterFieldDefinitions
        Dim crParameterFieldDefinition As ParameterFieldDefinition
        Dim crParameterValues As New ParameterValues
        Dim crParameterDiscreteValue As New ParameterDiscreteValue

       
        crParameterDiscreteValue.Value = ddlSubCat.SelectedValue.ToString
        crParameterFieldDefinitions = cryRpt.DataDefinition.ParameterFields
        crParameterFieldDefinition = crParameterFieldDefinitions.Item("@SUBCATID")
        crParameterValues = crParameterFieldDefinition.CurrentValues

        crParameterValues.Clear()
        crParameterValues.Add(crParameterDiscreteValue)
        crParameterFieldDefinition.ApplyCurrentValues(crParameterValues)

        CrystalReportViewer.ReportSource = cryRpt
        btnPrnt.Visible = True
        btnPDF.Visible = True
    End Sub