When updating from a previous version you: 

- May log on as Administrator or GCADMIN to the Exchange server
- Open the component manager on the server
- Find the ExchGC component 
- See if it is moving or not.

If it is moving, right click it and shut it down or wait a minute or two for it to stop moving.

Then run the Exchange GroupCalendar.exe
This will update both the ExchGC COM+ component and the GCADMIN.EXE tool to the new version.

