MAPI Status Error on OCS 2007 R2 Client

I am using OCS 2007 R2 Client Version 3.5.6907.206. I already installed the latest Microsoft Office Communicator 2007 R2 Hotfix KB 2028888. but I am still getting MAPI Error on some of my  XP machines. We are using outlook 2007 client.

I also verify autodiscover and Exchange Web Services links. We are using OCS only for internal network so no firewall problem either.

DG URL Internal;https://SRVOCS01.ABC.LOCAL/GroupExpansion/Int/service.asmx;--;

DG URL External;;--;

Quality Metrics URI;;--;

URL Internal From Server;https://SRVOCS01.ABC.LOCAL/Abs/Int/Handler;--;

URL External From Server;;--;

Voice mail URI;sip:abaig@diabetes.org;opaque=app:voicemail;--;

MRAS Server;;Not Configured;

GAL Status;https://SRVOCS01.ABC.LOCAL/Abs/Int/Handler;--;

Controlled Phones;TRUE;--;

PC to PC AV Encryption;AV Encryption Enforced;--;

Focus Factory;sip:test@abc.com;gruu;opaque=app:conf:focusfactory;--;

Telephony Mode;Telephony Mode Disabled;--;

Line;;--;

Line Configured From;Auto Line Configuration;--;

Location Profile;;--;

Local Log Folder;C:\Documents and Settings\test\tracing;;

MAPI Information;Communicator could not retrieve calendar or Out of Office information from Exchange Web Services. Communicator will automatically continue to retry. If this problem persists, contact your system administrator.;MAPI Status Error;

Inside User Status;TRUE;;

Auto Update Download Started;--;--;

Auto Update Download Completed;--;--;

Last Auto Update Request;--;--;

Pairing State;Communicator cannot connect to your desk phone because the USB cable is not plugged in. Make sure that you connect the cable.;Enabled;

Please help.