Maybe whatever user you're logged in as doesn't have permissions to that section? Are you logged in as the Administrator? That account should have permissions for everything.
What version of CalendarScript are you using??
** Am I not looking in the right place? **
My menu goes:
Global Options
* Manage Calendars
* Manage Plugins
* Admin Interface <--------
* Feedback/Support
JFYI
Dan O.
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