[AccessD] Hiding an object

Hi Group --

Using Access 2K - DAO

I am trying to display a subform only if there are related
records.

I have tried using Hide and Access says it does not support this Method.

Then I tried

If IsNull (cboProc.Column(0)) Then
Forms!frmAppointment.sfrmDental.Visible = False

This is actually a subform on a subform on a form.

Then I get an Object-Defined error.

Can I reference Subforms this way?

Thankyou for any help,

Bridget