Free/Busy synchronization is not working and errors are recorded in ACSAlerts.log file (4218467)

Free/Busy information is not populated for QCS (Quest Collaboration Services) publications and the following messages can be found in the logs:

"[2008/10/20 22:26:21.399] (2) Warning :<Exchange Layer> (32621) Public folders not found or unavailable."

QCS 3.0 has new software requirements. From documentation:
"Additional Software
Collaboration Services requires the following:
-Microsoft Exchange Server MAPI Client and Collaboration Data Objects 1.2.1 
-Microsoft Internet Explorer 5.0, 6.0 or 7.0
-Microsoft Windows Installer 2.0 or later
-Microsoft Internet Information Server (IIS) 5.0 or later (optional)"

Installing Microsoft Exchange Server MAPI Client and Collaboration Data Objects 1.2.1 package resolves such warnings:
Warning :<Exchange Layer> (32621) Public folders not found or unavailable.