Rapports recordsource ændring runtime

Hej

Jeg får en lidt mystisk fejlmeddelelse i :
Postkilden "Select bla. bla." der er angivet i denne formular eller rapport findes ikke.

' This code was originally written by Andy Baron
' It is not to be altered or distributed,
' except as part of an application.
' You are free to use it in any application,
' provided the copyright notice is left unchanged.
'
' Code Courtesy of
' Andy Baron

' er indsat i rapport
Private Sub Report_Open(Cancel As Integer)
  Me.RecordSource = grst.Name
End Sub

Public grst As Recordset

Public Sub testreport()
  Set grst = CurrentDb.OpenRecordset( _
        "Select * from tblTest1 where longfield=4")
  DoCmd.OpenReport "rptTest1", acViewPreview 
  grst.Close 
  Set grst = Nothing
End Sub

Har stirret mig blind - måske nogen kan hjælpe?