havin trouble with a sub report

[ZidaneXero]

So i need to add a supreport to the main report that i have and im not sure how to do that so i google it and im not getting it right

can anyone help me here please :$

Dim strConnection As String = "Server=OADMIN\SQLEXPRESS; Database=EHV2;uid=admin;Password=ehvgem"
        Dim Connection As New SqlConnection(strConnection)

        Dim norden As String
        norden = TextBox1.Text.ToString
        Dim strSQL As String = " (SQL Query) "
        Dim DA As New SqlDataAdapter(strSQL, Connection)
        Dim DS As New DataSet
        Dim strReportName As String

        DA.Fill(DS)
        'Pass the reportname to string 

        strReportName = "poReport2"

        'Get the Report Location
        Dim strReportPath As String = "C:\" & strReportName & ".rpt"

        'Check file exists
        If Not IO.File.Exists(strReportPath) Then
            Throw (New Exception("Unable to locate report file:" & vbCrLf & strReportPath))
        End If
        'Assign the datasource and set the properties for Report viewer
        Dim rptDocument As New CrystalDecisions.CrystalReports.Engine.ReportDocument


        rptDocument.Load(strReportPath)
        rptDocument.SetDatabaseLogon("admin", "ehvgem")
        rptDocument.SetDataSource(DS.Tables(0))

[B]'this should get the subreport filled with data        [B]rptDocument.OpenSubreport("subreport2.rpt").SetDataSource(DS.Tables(0))[/B][/B]


        rptViewer.ShowRefreshButton = False
        rptViewer.ShowCloseButton = False
        rptViewer.ShowGroupTreeButton = False
        rptViewer.ReportSource = rptDocument

It keeps telling me this:
Object reference not set to an instance of an object.

and that i should use this "Use the New keyword to create the instance. "

The thing is that the sub report should be a copy of the main report.

Thanks in advance