Manually configure the Oracle 10g EM dbconsole

Now start the Oracle EM dbconsole Build Script ($ORACLE_HOME/bin/emca for Linux and $ORACLE_HOME\Bin\emca.bat for Windows)
$ emca -repos create
$ emca -config dbcontrol db
http://192.168.177.128:1158/em

Recriando o Console de Manutenção Database Oracle 10g

1. Manually Resolve:
$ rm -rf $ORACLE_HOME/$hostname_$DBNAME

SQL> sqlplus /nolog
SQL> connect as sysdba
SQL> drop user sysman cascade;
SQL> drop public synonym setemviewusercontext;
SQL> drop role mgmt_user;
SQL> drop public synonym mgmt_target_blackouts;
SQL> drop user mgmt_view cascade;
SQL> alter system disable restricted session;

And then,

$ emca -deconfig dbcontrol db
$ emca -config dbcontrol db -repos create
$ emca -upgrade db

2. Using RepManager:
If I drop the Repository using RepManager like following error will not come while creating repository.
$ORACLE_HOME/sysman/admin/emdrep/bin/RepManager -action drop

This will not remove the configuration files, but only the repository related objects from the database.