$ oerr pgo 1024
1024, 0, "System default option values taken from: "

$ oerr pgo 66
66 , 0, "CMD-LINE:  Could not find or could not open system config file"
//    *Cause: The system configuration file has a standard name (pmscfg.h)
//            and a location that is operating system dependent. On UNIX
//            systems, it is located in the ORACLE_HOME/proc directory. If
//            a file named pmscfg.h is not found in the standard location,
//            this warning message is issued.
//    *Action: Create a system configuration file in the standard location.
//             The file can be empty. See also the operating system specific
//             Oracle documentation.