Thanks for letting us know about this. It is most likely that the security settings on your Internet Explorer browser are blocking the installation of the Active X component. If this is the case, you should see a tan or grey bar across the top of your browser when you visit the Auctiva Uploader page indicating the site is trying to install something and you should be able to right click that bar and accept the installation.
Once you have accepted the installation and the Active X component has been successfully installed, you should be able to use the Auctiva Uploader once again.
If you need further assistance with this, please feel free to contact our customer support team using the form on the following page of our site: http://www.auctiva.com/help/requesthelp.aspx