Error 2812 Could not Find Stored Procedure msdb.dbo.sp_add_jobstep_internal

Getting this error when trying to create an instance as a Publisher.
SQL Server 2000 SP4
reinstalled SP4 and that doesn't help
Error 2812 Could not Find Stored Procedure
msdb.dbo.sp_add_jobstep_internal
Probably the easiest solution is to reinstall sp4 (on distributor, publisher
then subscriber). It might be possible to selectively install the
replication scripts but we don't know what else didn't install correctly
(possibly some info in the sp install log file for this) so I'd simply
reinstall sp4 as the simplest way out.
Cheers,
Paul Ibison SQL Server MVP, www.replicationanswers.com