IHTMLFrameBase2.getcontentWindow throws COMException: 80004002: No such interface supported

I used njawin to generate mshtml and shdocvw in order to control Internet
Explorer... all the methods work great until I called the getcontentWindow
on IHTMLFrameBase2... any ideas why this is happening?


Method Called on IHTMLFrameBase2:

public IHTMLWindow2 getcontentWindow() throws COMException {
    return new IHTMLWindow2((DispatchPtr) get("contentWindow"));
}


Stack Trace:

com.develop.jawin.COMException: 80004002: No such interface supported

 at com.develop.jawin.marshal.GenericStub.dispatchInvoke0(Native
Method)
 at com.develop.jawin.marshal.GenericStub.dispatchInvoke(Unknown
Source)
 at com.develop.jawin.DispatchPtr.getN(Unknown Source)
 at com.develop.jawin.DispatchPtr.get(Unknown Source)
 at jcom.nextjet.MSHTML.IHTMLFrameBase2.getcontentWindow(Unknown
Source)
 at control.IExplorer.getFrameContent(IExplorer.java:233)