EMCA_数据库实例不可用

C:\>emca -config dbcontrol db

EMCA 开始于 2012-11-1 17:08:19
EM Configuration Assistant, 11.2.0.0.2 正式版
版权所有 (c) 2003, 2005, Oracle。保留所有权利。

输入以下信息:
数据库 SID: abc
Exception in thread "main" oracle.sysman.emcp.exception.DatabaseUnavailableException: 数据库实例不可用。
        at oracle.sysman.emcp.DatabaseChecks.throwDBUnavailableException(DatabaseChecks.java:151)
        at oracle.sysman.emcp.DatabaseChecks.checkDbAvailabilityImpl(DatabaseChecks.java:144)
        at oracle.sysman.emcp.DatabaseChecks.checkDbAvailability(DatabaseChecks.java:163)
        at oracle.sysman.emcp.DatabaseChecks.getDbServiceName(DatabaseChecks.java:582)
        at oracle.sysman.emcp.EMConfigAssistant.performConfiguration(EMConfigAssistant.java:1272)
        at oracle.sysman.emcp.EMConfigAssistant.statusMain(EMConfigAssistant.java:574)
        at oracle.sysman.emcp.EMConfigAssistant.main(EMConfigAssistant.java:522)