Hi,
The issue is resolved. Had to add the below line of code in my application in Application,js.
jQuery.sap.require("sap.ui.app.Application");
Found the solution from this link :
http://stackoverflow.com/questions/22188469/what-is-applicationbase-in-ui5-developer-guide
The issue is resolved, but wondering why did I have to declare the sap.ui.app.Application after upgrading to SP08. The application worked fine prior to the upgrade..
Thanks
Kalpana