I have started up oracle 10g for linux under sqlpus,
but when i enter the url: http://haier:5500/em, the web page always shows messages as follows:

The database status is currently unavailable. It is possible that the database is in mount or nomount state. Click 'Startup' to obtain the current status and open the database. If the database cannot be opened, click 'Perform Recovery' to perform an appropriate recovery operation.


but actually the database was already started up.

what's the reason and how to solve it? Thank you, I am waitting online. be anxious!!!

Be sure you have start Listener before you start oem with emctl.
And check the logfile in $ORACLE_HOME/<your site name>/log
You may find some error in :
emagent.trc or emoms.log and etc.

following is the content pasted from the emoms.log:

[oracle@haier log]$ tail emoms.log
        at oracle.sysman.eml.app.ContextInitFilter.doFilter(ContextInitFilter.java:193)
        at com.evermind.server.http.ServletRequestDispatcher.invoke(ServletRequestDispatcher.java:604)
        at com.evermind.server.http.ServletRequestDispatcher.forwardInternal(ServletRequestDispatcher.java:317)
        at com.evermind.server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:790)
        at com.evermind.server.http.HttpRequestHandler.run(HttpRequestHandler.java:270)
        at com.evermind.server.http.HttpRequestHandler.run(HttpRequestHandler.java:112)
        at com.evermind.util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:192)
        at java.lang.Thread.run(Thread.java:534)
2004-05-23 22:08:17,693 [HttpRequestHandler-4496124] ERROR eml.OMSHandshake getParameterFromDB.402 - Io exception: The Network Adapter could not establish the connection
2004-05-23 22:08:17,694 [HttpRequestHandler-4496124] ERROR eml.OMSHandshake processFailure.619 - OMSHandshake failed.(AGENT URL = http://haier:1830/emd/main)(ERROR = INTERNAL_ERROR)
[oracle@haier log]$


additional
I confirmed the listener had been started and emagent.log has no error messges.

the content after executed lsnrctl status


Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=172.16.8.1)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 10.1.0.2.0 - Production
Start Date                23-MAY-2004 22:50:22
Uptime                    0 days 0 hr. 0 min. 33 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/10.1.0/db_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/product/10.1.0/db_1/network/log/listener.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=172.16.8.1)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
  Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "focdb" has 1 instance(s).
  Instance "ora8", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully

emctl dbconsole start

lsnrctl status