problem in passing the integer value in crystal reports

[mshravs]

here i'm using crystal reports for passing an integer value and here is the code.

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim cryRpt As New ReportDocument
        cryRpt.Load("C:\Documents and Settings\user\My Documents\Visual Studio 2005\WebSites\gatepass\CrystalReport2.rpt")
        Dim crParameterFieldDefinitions As ParameterFieldDefinitions
        Dim crParameterFieldDefinition As ParameterFieldDefinition
        Dim crParameterValues As New ParameterValues
        Dim crParameterDiscreteValue As New ParameterDiscreteValue
        crParameterDiscreteValue.Value = Convert.ToInt32(TextBox1.Text)
        crParameterFieldDefinitions = _
                               cryRpt.DataDefinition.ParameterFields
        crParameterFieldDefinition = _
                               crParameterFieldDefinitions.Item("serial no")
        crParameterValues = crParameterFieldDefinition.CurrentValues
        crParameterValues.Clear()
        crParameterValues.Add(crParameterDiscreteValue)
        crParameterFieldDefinition.ApplyCurrentValues(crParameterValues)
        CrystalReportViewer1.ReportSource = cryRpt
        CrystalReportViewer1.RefreshReport()
    End Sub

but when i am running this it giving an error that
The report you requested requires further information

what more information do i require for the above code