Endpoint Protection Database Down issue

Hello,

I have a Endpoint Protection Small Business Edition.

in these days I receive email titled "Database is down"

I searched for this issue on internet and found some webpage

http://www.symantec.com/connect/articles/how-perfo...
http://www.symantec.com/connect/forums/symantec-en...

followed this guide, I could restart database service.

One different thing from the guide,

When I tried to execute the Query "DROP INDEX I_SEM_AGENT_COMPUTER_ID_PLUS",

dbisqlc.exe reports error "Cannot find index named 'I_SEM_AGENT_COMPUTER_ID_PLUS'"

Anyway the database runs again, but after some hours, it goes down again and again.

How can I solve this problem?

Thanks,

Kim