When setting up Log Shipping on SQL Server 2000 you may receive the following error:

could not find msdb.dbo.sp_define_log_shipping_monitor

When you upgrade a SQL Server 2000 instance from SQL Server 2000 Standard Edition to SQL Server 2000 Enterprise edition the log shipping objects are not created, hence the error. In order to create the log shipping objects you need to run the log shipping installation script, instls.sql, which is located in the \Install folder of the SQL Server 2000 Enterprise edition CD.