Minimal system requirements:

To run GroupCalendar™ one needs:

Windows® 95 or higher with all service packs *
Office 2000 or higher with all service packs *
A network connection and a computer with a shared folder where all users have read/write security rights

On some Windows ® 95 / 98  and 2000 pc's the Windows ® Scripting host is not installed. This will result in an  error message number 91 after installing GroupCalendar™.
This can be fixed by installing WSH from the following locations.

Windows® 2000 en XP  
Windows® 98, Windows® Millennium Edition, en  Windows® NT 4.0  

* It's highly recommende to make sure that the Windows® and Office software is fully patched. Service packs fix problems that are being discovered after initial release of the software. GroupCalendar might not always work as expected when those patches are not in place.
Microsoft®  has made it easy to install updates. If you visit the website http://windowsupdate.microsoft.com it's a matter of clicking the Scan button to scan for and install the available patches. For Office / Outlook® another website must be visited to scan for updates: http://office.microsoft.com