Got this error after a 11gR2 database clone. oracle [prod] logs $ emctl status dbconsole OC4J Configuration issue. /u01/app/oracle/product/11.2.0.4/db_1/oc4j/j2ee/OC4J_DBConsole_hostname_prod not found. Just drop and recreate the repository and the configuration as follows - be aware this action will quiesce the database - and potentially impact operations
emca -deconfig dbcontrol db -repos drop
emca -config dbcontrol db -repos recreate