How to Configure OEM 10g Database Control after Clone

After cloning an EBS environment I had tried to start the OEM 10g Database Control (DBConsole) and I got this message: [oratest@testsrv1 ~]$ emctl start dbconsole TZ set to Israel OC4J Configuration issue. /oracle/test/db/testdb/10.2/ oc4j/j2ee/OC4J_DBConsole_testsrv1.domain_TEST not found. However, it was an acceptable message since DB Console wasn't configured to this instance yet. Using emca I've tried to recreate the DB Control configuration files as follow: [oratest@testsrv1 ~]$ emca -config dbcontrol db ... INFO: Database Control started successfully ... INFO: >>>>>>>>>>> The Database Control URL is http://testsrv1.domain:5500/em <<<<<<<<<<< Enterprise Manager configuration completed successfully Well, I thought it looks fine, but when I opened the DB Console I saw this message at the top of the page:  error: java.lang.Exception: Exception in sending Request :: null After some research, logs digging and Metalink searches, I found that the Agent component should be relinked manually. But before there are two issues in env_sysman.mk file that should be fixed before executing the relink command. I will show my actions step by step: Stop DB Console: emctl stop dbconsole   cd $ORACLE_HOME/sysman/lib   Edit env_sysman.mk and look for "JRE_LIB_DIR" In my instance JRE_LIB_DIR was populated with the old environment name.. I changed it from: JRE_LIB_DIR=/oracle/prod/db/proddb/10.2/jdk/jre/lib/i386 To: JRE_LIB_DIR=/oracle/test/db/testdb/10.2/jdk/jre/lib/i386   One more issue for env_sysman.mk, look for "$(LIBNMEM)  $(LIBNMER)" And change from: $(LIBNMEM)  $(LIBNMER) \ To: $(LIBNMEM)  $(LIBNMER) $(LIBNMO) \   Now relink the Agent component by issuing this command: make -f ins_sysman.mk agent   Recreate the DB Control configuration files (Again, even if you did it before) emca -config dbcontrol db Following this procedure will make the DBConsole configured and work for the new cloned instance.