Here is my experience in resolving EM problem. This is meant for students who like to trouble shoot. The complete document on EMCA is available at Oracle's web site. (2/10/09)

Problem: Oracle Enterprise Manager was not configured successfully, and did not function.

Version: Oracle 11g

OS: Windows XP Professional

Lessons Learned:

The DBConsole configuration problem can be resolved using EMCA utility.

1. To drop the EM:

C:\emca -deconfig dbcontrol db -repos drop

Enter:

SID: the name of your database.
port number: 1521

2. To recreate EM:

C:\>emca -config dbcontrol db -repos create -respFile c:\temp\emca_infile.txt

The emca_infile.txt provides input parameters, which consists the following:

PORT=1521

SID=oracle

SYS_PWD=pingliu

DBSNMP_PWD=pingliu

SYSMAN_PWD=pingliu

AGENT_PORT=3938

DBCONTROL_HTTP_PORT= 1158

RMI_PORT=5520

JMS_PORT=5540

The above parameters can be entered interactively if you use:

C:\>emca -config dbcontrol db -repos create

I used the above file to save some typing and retyping.