When starting the intelligent agent from the server I get the this error message:
LSNRCTL> Failed to initialize nl component,error=280
Failed to initialize nl component,error=280

How can I fix the problem?

By: John Kazerooni

1 – Make sure that the TNS_ADMIN and ORATAB environment variables have correct entries.

2 – Make sure that the AUTOMATIC_IPC=OFF parameter is in the SQLNET.ora.

3 – Make sure that the account DBSNMP/DBSNMP was created.

4 - Run root.sh. This will cause the dbsnmp executable to be own by root and to set the setuid bit.

5 – Make sure that all the keywords in your LISTENER.ORA and TNSNAMES.ORA files are all in UPPERCASE.

6 – Make sure that the value returned when issuing the UNIX command "hostname" matches the TNSNAMES.ORA
reference to host.

7 - Ensure that the /etc/hosts file contains the hostname.

8 - Relink the agent executable:
% cd $ORACLE_HOME/network/lib
% make -f ins_agent.mk install

9 - Delete the $ORACLE_HOME/network/admin/SNMP_*.ORA files. Delete all the files in the $ORACLE_HOME/network/agent directory, leaving only the subdirectories.

10 - Set the environment variable: ORATAB & TNS_ADMIN
setenv ORATAB /etc/oratab or /var/opt/oracle/oratab <--use the exact oratab location
setenv TNS_ADMIN /u04/oracle/network/admin <--use the exact location of sqlnet config files.

11 - Verify that the ORATAB file contains only valid SIDs and ORACLE_HOMEs. Invalid entries in the ORATAB file causes the Oracle Intelligent Agent not to start.

12 - Remove/rename all files in your $ORACLE_HOME/network/log directory. Files owned by root may cause problems.

Good Luck!