Crystal Report

Question

I am preparing a crystal report for library system... two tables..

1)BookIssueDetail:

fields : grno ,bookno,issuedat

2)studentMaster

fileds: grno,stdename,(and lots more)..only these filed are req to display...

now i have made a dataset : "bookissuedataset" which have two table which are assign above.

these is my code on print button

Dim str, str1 As String
        Dim bookno As Integer

    str1 = "Select bookno from bookmaster where bookname = '" + cmbName.Text + "'"
    cmd = New OleDbCommand(str1, cn)
    dr = cmd.ExecuteReader

    If dr.HasRows Then
        While dr.Read
            bookno = dr(0).ToString
        End While
    End If

    Dim l As New BookIssueDetail  //this is my report name

 str = "select BookIssueDetail.grno,StudentMaster.StudentName,BookIssueDetail.BookNo,BookIssueDetail.IssueDate from BookIssueDetail inner join studentmaster on studentmaster.grno=BookIssueDetail.grno where BookIssueDetail.bookno =" + bookno.ToString

da = New OleDbDataAdapter(str, cn)
    Dim ds As New DataSet
    da.Fill(ds, "BookIssueDetail,StudentMaster")
    l.SetDataSource(ds)


    Dim frm As New frmReportVeiwer(l) //this call a new form which have only                                         reportviewer added in it.its code is                                           dislpaly below
    frm.Show()

Public Class frmReportVeiwer

Public Sub New(ByVal l As CrystalDecisions.CrystalReports.Engine.ReportDocument)
    InitializeComponent()
    CrystalReportViewer1.ReportSource = l
    CrystalReportViewer1.Refresh()
End Sub


End Class

this is my code...this work fine when i have only one table in my dataset but when i have 2 or more table in my dataset then my crystal report cpe blank.no field is displayed.. ..all d report dislay all the field when i have only one table in my dataset..

please guide me in this matter.. i don't know i m missing a big ort small point here but this thing is killing me...my almost proj is done but i am stuck on this thing..