Install JVM for Oracle 11g XE

Just guesswork, but do you select "Upgrade an existing database" early on:

and "advanced install" later on:

The docs do look as if they are referring to the 10g installer.

Scheduler agent is part of database Oracle Home. Anyway must be manually deployed; there is no way to use the database as agent. I think that the documentation is misleading on this case. To help you I will write steps to be performed for agent configuration. I suppose that on the central database you have already enabled HTTP port (etc.). On the remote database (the one where agent have to be configure):

cd $ORACLE_HOME\bin
extjobo -createagentzip execution_agent.zip

Unzip the file into a directory under the $ORACLE_HOME\scheduler.

cd $ORACLE_HOME\scheduler
unzip execution_agent.zip

Modify the file named schagent.conf located in the $ORACLE_HOME\scheduler\execution_agent directory setting the Scheduler Agent port number to listen for connections. (the one you should have already set with dbms_xdb.sethttpport() )

PORT=<schagent_port>

You have to run the root.sh to fix the uid. (You can follow the README file in the execution_agent directory and run the root.sh). NOTE Verify a directory named /wallet exists under /execution_agent/data before running root.sh. If not create them manually and then run root.sh.

Register the database with.

set ORACLE_SID=<your sid>
cd $ORACLE_HOME\scheduler\execution_agent\bin
schagent -registerdatabase <db_host> <db_http_port>

You will be asked to input the registration password. Last start manually the agent:

schagent -start

These steps will install and configure the agent. Now you can create credentials on the central database and create the database destination. Database destination can exists along with a remote agent destination.