Yes, you can't add a form to a form.

oForm = CreateObject("form")
oForm.AddObject("oForm2","form")

gives you the same error. A form isn't allowed to have a parent object other than a formset.

But why do you want to put form2 into form1? To reuse the datasession? simply set the Datasession property of your form2 class to 0 - standard datasession, then it will scope into the same datasession the object has, which creates the form. And then don't add the second form, but simply do thisform.oSecondform = Createobject("form2").

Bye, Olaf.