Hi Dan,
The reason for above error is the operation mapping object is not there in the CPA Cache of decentral adapter engine, when you activate the object it suppose to automatically update the DAE CPA cache also.
Is de-central adapter engine registered in SLD with same domain of central adapter engine? can you able to see DAE in the drop down list of adapter engine parameter in the channel configuration. If you can able to see then check is the cache is green for DAE instance in the repository and directory cache notifications.
When you activate the change in the repository the notification will send to directory, directory will fetch the object and update the cache in all adapter engines resisted in the same domain, i think there is connectivity problem between directory and DAE, you can find these errors in cache notification tables in the repository and directory.
Regards,
Praveen.