oem 报错“java.lang.Exception: IOException in sending Request :: Connection refused“错误

今天在用EM进行SQL TUNNNING时发现oracle 10g R2下EM得一个报错，错误如下 ：“java.lang.Exception:IOException in sending Request :: Connection refused: connect”，遂通过查阅资料得到如下解决方案。步骤如下：
1.停止emagent:[oracle@prod~]$ emctl stop agentTZset to PRCOracleEnterprise Manager 10g Database Control Release 10.2.0.1.0Copyright(c) 1996, 2005 Oracle Corporation. Allrights reserved.Thiswill stop the Oracle Enterprise Manager 10g Database Control process. Continue[y/n] :yStoppingOracle Enterprise Manager 10g Database Control …… Stopped.Agentis not running.2.重新设置时区[oracle@prod~]$ emctl resetTZ agentTZset to PRCOracleEnterprise Manager 10g Database Control Release 10.2.0.1.0Copyright(c) 1996, 2005 Oracle Corporation. Allrights reserved.Updating/u01/app/oracle/product/10.2/db_1/prod.oracle.com_prod/sysman/config/emd.properties…Timezone set to PRC.
Tocomplete this process, you must either:
connectto the database served by this DBConsole as user ‘sysman’, and execute:
SQL>exec mgmt_target.set_agent_tzrgn(‘prod.oracle.com:3938′,’PRC’)
– or –
connectto the database served by this DBConsole as user ‘sys’, and execute:
SQL>alter session set current_schema = SYSMAN;SQL>exec mgmt_target.set_agent_tzrgn(‘prod.oracle.com:3938′,’PRC’)
根据提示进行设置
3、时区设置
[oracle@prod~]$ sqlplus / as sysdba
SQL*Plus:Release 10.2.0.1.0 – Production on Sat Oct 29 11:54:16 2011
Copyright(c) 1982, 2005, Oracle. All rightsreserved.

Connectedto:OracleDatabase 10g Enterprise Edition Release 10.2.0.1.0 – ProductionWiththe Partitioning, OLAP and Data Mining options
SQL>alter session set current_schema = SYSMAN;
Sessionaltered.
SQL>exec mgmt_target.set_agent_tzrgn(‘prod.oracle.com:3938′,’PRC’)
PL/SQLprocedure successfully completed.
SQL>exitDisconnectedfrom Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 – ProductionWiththe Partitioning, OLAP and Data Mining options
4.启动emconsole[oracle@prod~]$ emctl start agentTZset to PRCOracleEnterprise Manager 10g Database Control Release 10.2.0.1.0Copyright(c) 1996, 2005 Oracle Corporation. Allrights reserved.Startingagent … started.[oracle@prod~]$ emctl stop dbconsoleTZset to PRCOracleEnterprise Manager 10g Database Control Release 10.2.0.1.0Copyright(c) 1996, 2005 Oracle Corporation. Allrights reserved.http://prod.oracle.com:1158/em/console/aboutApplicationStoppingOracle Enterprise Manager 10g Database Control …
Cannot determine Oracle Enterprise Manager 10gDatabase Control process./u01/app/oracle/product/10.2/db_1/prod.oracle.com_prod/emctl.pid does notexist.[oracle@prod~]$ emctl start dbconsoleTZset to PRCOracleEnterprise Manager 10g Database Control Release 10.2.0.1.0Copyright(c) 1996, 2005 Oracle Corporation. Allrights reserved.http://prod.oracle.com:1158/em/console/aboutApplicationAgentVersion : 10.1.0.4.1OMSVersion : UnknownProtocolVersion : 10.1.0.2.0AgentHome :/u01/app/oracle/product/10.2/db_1/prod.oracle.com_prodAgentbinaries :/u01/app/oracle/product/10.2/db_1AgentProcess ID : 12581ParentProcess ID : 12578AgentURL :http://prod.oracle.com:3938/emd/mainStartedat : 2011-10-29 11:55:00Startedby user : oracleLastReload : 2011-10-29 11:55:00Lastsuccessful upload none)Lastattempted upload none)TotalMegabytes of XML files uploaded so far : 0.00Numberof XML files pending upload : 15Sizeof XML files pending upload(MB) : 2.41Availabledisk space on upload filesystem : 79.74%Agentis already started. Will restart the agentStoppingagent … stopped.StartingOracle Enterprise Manager 10g Database Control …………………….started.——————————————————————Logsare generated in directory/u01/app/oracle/product/10.2/db_1/prod.oracle.com_prod/sysman/log