Cannot enable data definition language (DDL) replication (a value of "true" for the @replicate_ddl parameter) for publication ...

Cannot enable data definition language (DDL) replication (a value of "true" for the @replicate_ddl parameter) for publication "%1!s!". This is because the compatibility level of the publication is lower than 90RTM. For new publications, in the stored procedure sp_addmergepublication, set the @publication_compatibility_level parameter to 90RTM; for existing publications, use sp_changemergepublication.