Problem logging to Vtiger CRM through Microsoft Outlook

Hi,
I am working on a test version of VtigerCRM 5.0.3.I am trying to synchronise the calendar of VtigerCRM with the calendar of Microsoft Outlook.I have installed Vtiger CRM 5.0.3 Outlook plugin.
When i try to login to Vtiger CRM via Microsoft Outlook 2003,it says MSXML objects cannot be initialised.
Please tell me if you have any wayout.

Thanks
Bye