Hi Vijay,
As per the install guide for MPX 1.x as well as 2.x "Caution! Be sure you enter the correct date and time. You must reinstall the Cisco Unified MeetingPlace Express operating system and application if you need to change the date or time of your server in the future."
http://docwiki.cisco.com/wiki/Cisco_Unified_MeetingPlace_Express,_Release_2.x_--_Configuring_the_Cisco_Unified_MeetingPlace_Express_Server#Configuring_the_Cisco_Unified_MeetingPlace_Express_Server
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/meetingplace_express/1_2/english/installation/guide/iug/mpxinst3.html
HTH
Manish
