Problema no start dbconsole

Oi pessoal, sou nova aqui no fórum.

Estou tentando acessar o enterprise manager.

Quando executo o comando "emctl start dbconsole" aparece o seguinte erro:

[oracle@ bin]$ emctl start dbconsole

The following exception occurred:

java.net.UnknownHostException: .: .

at java.net.InetAddress.getLocalHost(InetAddress.java:1354)

at oracle.sysman.emd.targetIntg.agent.AgentTargetInstaller.getLocalHost(AgentTargetInstaller.java:4282)

at oracle.sysman.emd.targetIntg.agent.AgentTargetInstaller.printLocalHost(AgentTargetInstaller.java:4252)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:597)

at oracle.sysman.emd.targetIntg.Util$DefaultIntegrationMethod.execute(Util.java:598)

at oracle.sysman.emd.targetIntg.TargetInstaller.execute_(TargetInstaller.java:167)

at oracle.sysman.emd.targetIntg.TargetInstaller.execute(TargetInstaller.java:155)

at oracle.sysman.emSDK.conf.TargetInstaller.printLocalHost(TargetInstaller.java:2364)

at oracle.sysman.emSDK.conf.TargetInstaller.main(TargetInstaller.java:3290)

Although there was an exception it might be possible for the program to continue.

OC4J Configuration issue. /home/oracle/app/oracle/product/11.2.0/dbhome_2/oc4j/j2ee/OC4J_DBConsole_null_orcl not found.

o que pode ter acontecido ?

se souberem me ajudem a solucionar...por favor.