MDI - MDI Child forms


My ActiveForm pops up a regular form, which i want it to be the MDI form,
and from this MDI form, i want to pop up a lot of MDI Child forms.  Does
Borland support this for ActiveX development?

or maybe i am doing something wrong, becuz it keeps complaining that no MDI
form is active:

        MainForm = new TMainForm(this);  //i want this to be my MDI form
        if (bExit) //cancel button is clicked on the MainForm
        {       MainForm->ShowModal();
                delete MainForm;

thanks in advance..!!

Je Je