[AccessD] still troubles with IsLoaded

Hello Group,

i keeping getting an error on the IsLoaded. "Sub or function not defined"
This was working in A97, but in 2003 it is giving me troubles.

i tried to Dim al objects, with no result.

I can't figure out why

Please help

Pedro Janssen



Private Sub pl_Form_Current()
On Error GoTo Err_Form_Current

    Dim strDocNaam As String
    Dim Koppelcriterium As String
        
        strDocNaam = "Produktenlijst"
        Koppelcriterium = "[Levcode] = Forms![Lev]![Levcode]"
   
    If IsNull(Me![LEVNAAM]) Then
        Exit Sub
    ElseIf IsLoaded("Produktenlijst") Then
        DoCmd.OpenForm strDocNaam, , , Koppelcriterium
    End If

Exit_Form_Current:
    Exit Sub
    
Err_Form_Current:
    MsgBox Err.Description
    Resume Exit_Form_Current

End Sub