HELP: Class not Found error in ActiveX DLL

I created an Automation object in an ActiveX DLL project.  In one of the
methods of the automation object, I create and display a form.  When I try
to invoke the method from a client application, I get the error +ACI-class
TTabSheet not found.+ACI-  The error occurs when creating the form.

Is there some way to make this work?