Mail notification for Free/Busy update

I’m receiving a New Mail notification whenever my computer receives Free/Busy data updates. If I click Yes to read the new mail Outlook tells me the custom form can’t be found and displays the update as an e-mail from “Microsoft Schedule+ Free/BusyConnector (SERVERNAME)” with garbage in the message. Why did this start and how do I make it stop? And if we don’t use Schedule+ then do I need to have this connector?