If you are using SQL 2005 for your MSP 331 database, and your SQL 2005 server is installed on Windows Server 2008 or 2008 R2, you MUST install SQL 2005 Service Pack 3. This must be done before running the MSP installer. If SP3 is not applied before running the MSP installer, the MSP install/upgrade will fail. See pg 29 of the MSP 331 Release Notes.