Event id 7888 in Eventviewer

A while ago I got a lot of error messages in Event Viewer on our MOSS server. I found the following solution:

run stsadm -o sync -DeleteOldDatabases 0

and the message disappears.
What it does is enter the table "sitesynch" on the SQL server and deletes connections to any old Sharepoint config database that you may have on your server.

The entire message:

A runtime exception was detected. Details follow.
Message: A duplicate site ID 3b2fa192-1efb-4715-970f-2e550122faf0(https://xxxx) was found. This might be caused by restoring a content database from one server farm into a different server farm without first removing the original database and then running stsadm -o preparetomove. If this is the cause, the stsadm -o preparetomove command can be used with the -OldContentDB command line option to resolve this issue.
Techinal Details:
Microsoft.Office.Server.UserProfiles.ProfileSynchronizationDuplicateSiteIDException: A duplicate site ID 3b2fa192-1efb-4715-970f-2e550122faf0(https://xxx) was found. This might be caused by restoring a content database from one server farm into a different server farm without first removing the original database and then running stsadm -o preparetomove. If this is the cause, the stsadm -o preparetomove command can be used with the -OldContentDB command line option to resolve this issue.
at Microsoft.Office.Server.UserProfiles.ContentDBSynchronizer.RegisterSitesForSynch(Guid[] rgGuid, Int32 nGuids, Object dummy)
at Microsoft.Office.Server.UserProfiles.SynchCollection`2.FlushAdds()
at Microsoft.Office.Server.UserProfiles.SynchCollection`2.Add(T objAdd)
at Microsoft.Office.Server.UserProfiles.ContentDBSynchronizer.AddRemoveSites(String strFirstChangeToken, SPChangeToken lastChangeToken)
at Microsoft.Office.Server.UserProfiles.ContentDBSynchronizer.SynchContentDB()
at Microsoft.Office.Server.Diagnostics.FirstChanceHandler.ExceptionFilter(Boolean fRethrowException, TryBlock tryBlock, FilterBlock filter, CatchBlock catchBlock, FinallyBlock finallyBlock)