MS Office Application in a Frame

How can I get the url/location/path of an office document which is displayed in a iframe of a browser (Internet Explorer)?

I've tried it with an ActiveX-Control: 'UserControl.Parent.Script.document.frames(0).document.location' --> no success

I got following error: runtimeerror
'-2147352573(80020003)': Member not found

Thanks a lot in advance

Reinhard