[Evolution] getting 'calendar is not a valid icalender' message when receiving calender from Outlook

[Muhammad Sharfuddin <M Sharfuddin nds com pk>]

Mail Server: MS Exchange 2007
OS: SLED 11 SP1 i586
Evolution Version: 2.28.2

Problem:
whenever a user(outlook) sends/share his/her calendar with someone using SLED11/Evo, the recipient receives a blank email, with following
error and the sender receives the invitation as accepted automatically.

    The message claims to contain a calendar. But the calendar is not a  valid icalender

Please help

--
Regards,
Muhammad Sharfuddin | NDS Technologies Pvt Ltd | cell: +92-333-2144823 | UAN: +92-21-111-111-142 ext: 113