AECOsim Mechanical tools stopped working

Hi,

I have AECOsim SS4, SS5 & SS6 versions on my machine and in all versions the mechanical tools have stopped working.

All dialogs for Place Duct or Diffuser etc. come up but nothing appears on the cursor to place.

I remember some years ago that registering the MSCOMCTL.OCX was required when this happened.

I have tried that, but it now brings up an error message and does not complete.

I am running Windows 7 Pro 64 Bit SP1

Any thoughts would be gratefully received...

Regards

John