Unable to share calendar in Outlook 2003

We recently installed Exchange on our server, mainly to be able to share calendars, etc. However, when I right click on Calendars and go to sharing, the Permissions tab is not there. I have tried repairing and re-installing Outlook, but it still doesn’t work. I have added a ghost user to my computer and when I log on as this user and go to Outlook, the Permissions tab is there. So, there must be a setting somewhere in my system that is not allowing this tab for me. If anyone can help, I would appreciate it!