HyperStudio 5 Web plug-in is needed to open exported stack.

Click here to download this plug-in from the Software MacKiev website. When downloading is complete, install the plug-in by double-clicking its Installer icon in the Finder.

Note: If you have the HyperStudio 5 CD, you can install the plug-in from there. Just insert the CD and double-click the HyperStudio 5 Web Plug-in icon in the dialog that appears.