Adprep was unable to extend the schema. Status/Consequence There is a schema conflict with Exchange 2000. The schema is not ...

Adprep was unable to extend the schema.
[Status/Consequence]
There is a schema conflict with Exchange 2000. The schema is not upgraded.
[User Action]
The schema conflict must be resolved before running adprep. Resolve the schema conflict, allow the change to replicate between all replication partners, and then run Adprep. For information on resolving the conflict, see Microsoft Knowledge Base article Q325379.