Got it :)
We wont be able to do much without SEM5.db, how many clients do you have in your network?
If you have less number of clients, you can run a complete fresh install of SEPM
then use the communication deployment wizard to bring back your clients to this new SEPM as per this document
http://www.symantec.com/business/support/index?page=content&id=HOWTO81109