What is a transport and how to configure it?

Hello,

I am using NW 04 Patch 11.

When users go to home->work there is a calander there.

The calander is not active and there is a message there:

"No transport has been configured for the calendar".

Can someone please explain me how do I get this calander to work, how do I configure a transport and is it possible to connect this calander to the user's exchange calander?

Roy