SIM 5.1 sp1 : lost connection to database

[OlivierV]

Hello.
nearly once a day, I have an event saying SIM has lost connection to database. In Mx.log, the message is :

@!@,2007-08-01 20:33:45 CEST,APPLICATION,FAILURE,DONE,CMS,HP Systems Insight Manager shutting down.[2001],ERROR,issesi03\mxadmin,,,
Lost connection to database, exception: java.sql.SQLException: Unable to get information from SQL Server: ISSESI03. SQL=

The SQL server is running on the same machine as the CMS with the same local admin account. The consequence is the performance management pack stops monitoring the servers excepted the CMS itself.

What could be the cause of this problem ?

Thank you.