The “Microsoft SQL Server” management pack failed to execute the SQL Server 2000 Replication Monitoring script successfully. The following error event was returned “Access denied while reading registry value [\\Your-MOM-Server\HKLM\Software\Microsoft\MSSQLServer\Setup\ProductCode]”. The following additional error details were returned “”. Please refer to the events associated with this alert to view the computers that have experienced this problem.
In reality, on my SQL2000 SP4 installation, this registry path does not exists. Looks like a BUG. My knowledge to SQL Scripting is very limited and so I have disabled SQL Server 2000 Replication Monitoring Script from MOM Admin Console:-). This script is located in State Monitoring and Service Discovery Event Rules container.
Make sure MOM ACTION account is a member of Built-in Users group on MOM Server. Built-in Users group has read permissions on HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer.